This is a reverse drill that builds up so take the lessons of the steps and enjoy. Start by closing one eye and walking in a small circle. Notice how your field of vision changes and with a partner position yourself so you define the limits of your field. Now start moving slowly (both of you). Your goal is to keep him or her out of your sight which is opposite to the primal urge to focus on moving objects and human faces. Notice items and boarders in your sight  (the grass and the shadow of the tree in it and the line that seperated the sand from the grass …) Don’t focus on the people if you are working within a crowd and keep searching all the time for what you haven’t noticed. This builds exellent observation skills and an ability to avoid being transfixed by sharp movements and seeing the second attacker. Reverse your eyes and than the roles and exchange your thoughts of what you felt during this drill. Did you both consider your goals met ? Did you adjust well ? and so forth. If you are steping into a low light enviroment or a sharp contrast from light to dark or in reverse use rapid blinking and looking from the sides of the eyes and closing one eye at a time to adjust. This maintains a low saturation in the different types of sensor cells you have in your eyes (sideways works best in low light) and working using one eye at low level light will build some mental undurance. especially if you are working in a forest of some other non level ground. Sunglasses at night are also a good way to train yourself to notice everything you are given by the senses. Take care and don’t forget to breath.

A few pieces of the ground puzzle: 

lie on your stomach and roll from side to side: Balance on the sides and continue, roll beginning with the legs, middle and shoulders. (I mean start the wave at the…)  Next lie on your back and curle into a ball by bringing the knees to the chest. Start with one knee and the next coming to the already formed shell. next lie on your back and put the mass on the shoulders as you move the hips to the side and than put the mass on the hips and move the shoulders and continue. next put the mass focus on one hip and the opposing heel and pivot the upper body from there to one side and the other. Make sure the arms are relaxed or helping by forming the right shape for the movement to pass well. I mean by that a very simple thing. We roll the shoulder as we roll from standing to the ground so the shape will be good for the movement. But it is also the rotation itself which lends to the actuall move done by the body. Next sit on your behind with arms and legs in the air and holding onto each other and srart to roll on the ground like a plate revloving on the sides of this formed cone. Next lie on your belly and keep the position of your ribs in mind (do they stick the ground ?) breath in and lift your head and shoulders off the ground. Exhale and relax downward. next breath in again and tilt the head to one side so you begin a roll to the side and don’t forget to push with your belly. next lie on your back and raise the hips with a push from the feet flat on the ground. As they are up. Sway here and there and see how you can roll to each side in this position without banging your hips to the ground or coming into unwanted contact between your face and the dirt. 

 Enjoy and play with there movement. Make your own and try to move continuesly on the ground without pause. It is a key to unlock what the body can do.

A nice mental drill is to get into tight spots per say and learn to work with them. for example: you kicked high and your leg was cought what do you do ? hit the hand that is holding your leg, do a scissor leg move, roll towards the leg, let him have the shoe as you get out of the grip ? kick the shin of his leg, grab his shirt or neck and use that as a counter lever and so on. next try working with a neck strangulation, two people on top of you (not the supermodel type, they have sharp bones and need protective gear Innocent) and the list goes on as far as you like. Situational spots are also good. For example one person acts the bully in a staircase or someone comes in and tries to steal your case as you are sitting on a bench. One person distracts you with an “honest question” as the other makes a grab at your child and so on. Remember to breath and keep moving. you will not always succeed but you can survive if you keep trying. 
Sometimes we roll without the benefit of knowing or seeing what is there. Try this. Stand and close your eyes. now have someone place a chair or something close to you so there is a reality of rolling into something and now roll. You may find that leading with your arms in a swiming motion (sweeping to the sides) works well. Another thing is that you will naturally protect your neck and head with your arms as you get up. And all of this out of your faithfull servant FEAR. Keep it in this position and it will be of great help.
Simple and to the point. Rollin with hands on the hips makes you aware and amplifies the tension you may have between the ribs or the hips and shoulders rectangular shape.  Start from standing and roll but go for the least amount of effort to get the job done. If you are afraid than use it. If you have fear from hitting yourself with the good ground simply sit down and roll from there. A nice way to do this is to sit down and roll backwards. That way the lazy person who slips doesn’t break his fall with his hand (notice the words) and can get up again without even trying. Try sitting down and getting up with hands on your hips without bending or tilting your torso. As you are seated and trying to get over gravity people often try to shorten the move and stress themselves by falling with the head forward and using the thrust to get up. Instead use the relaxation of the hips and legs to pivot up. The point of support is important and you need something to push against. If that something is to the side than it is hard to get up. If you have two things pushing towards each other than you have a wedge that doubles your work ability and if it is beneath you than you simply move the right way. If what I wrote makes little sense than simply sit down on your behind and start to play with your legs. Bring the shins beneath you and than you can lift one knee and push yourself up. You can spiral up if you sit on your behind and sorta push with both feet to the same side as the legs are bent and flat on the ground. If you keep the torso light and up you will simply get up. More on that later. I plan to post another video on utube as soon as I can make one. 
A nice way to learn to ease your breath and keep form is to stick a small object like a cell phone or a pen between the pants and the belt so it is held by the tension of your normal breath and walk and do regular things for a while. Than you have one or more jump at you using surprise or if you can in a house from different places like under the stairs and the like. You know if the object falls that you changed your breath by reacting rather than choosing what to do. This is a simple example and i am sure you can find ways to make it more relevant for you. 
Many times people say they are threatened by bullies and that makes sense. Bullies act outside the mutual agreement of politeness most people think they work with. So they allow the bully entry into their personal space or even to grab them and pull them off balance thinking it will all turn out fine. You choose what you do and you can use this mentality to your aid as well. If the bully puts a hand on your neck or shoulder and pushes you against a wall or pulls you toward a choke hold. He is giving you a lot of power you can use and a leverage point. A slight increase in speed will move out outside his range as he pushes you and you can run away (especially if his mates are in the reserve of the ego guard) if you are pushed against the wall you can slide down and slide his head into the wall as you go. Holding onto his belt or jewels will do the same as you simply drop to a sit down and you can make your own solution according to the simple principles here. Remember that there is always something worse. Unless we are talking about Brussel sprouts !!!
If you have a willing partner or even a family (blood or otherwise) member you can get a leg up on learning to move on the ground using this. Lie on the ground and have him or they take one leg or any limb and start to walk with it changing directions as he wants. Your job is to stay with him and untangled. feel how you can nagotiate the floor and use it to keep your sight of what is going on around you and stay moving. If you have trust and enough experience you can do this using the head or even eliminating arms or legs using ropes or any other tool. You can poke  your partner using a dull knife so he evades and than do so as you aldo lever him in some way or simply sit on him. We move around all day carrying all this mass so why no use it ? Drop on his back or lower belly. If he takes your balance away you can fall on top of him while avoiding the hard parts. Don’t forget that the head is easy to crack and has very little in way of sole reaction. Keep your learning fun and you will know that your mind is also healthy. Without that you are destroying parts of you and that will show eventually.

A few gorund movement basics: Start from sitting down on your behind. lift the torso and legs so you are on your behind and your hands are on the knees. Start to rock like a boat forward and backwards as a whole. Think the body as a one piece of wood (yea I know) so everything moves together. Now rock from side to side shifting the mass or pressing each hip to the ground at a time.  Once those are “mastered” you can do rounds and play with it. Next streatch the body on the ground and press your mass to one shoulder and oposing knee or foot. You create a mini bridge and use the imbalance to turn the body on the axis this creates. If you want to shift sides you need a bigger arch so use the foot flat on the ground or heel pressed to the ground. One nice way to use this is to hit the shins of an approaching person. you wait for the right moment and turn as if you are rolling ups his shins. You can add a hit if you think it is needed and take a better look on all that is around you. To better incorporate you breath into this try to jump whine in this “boat position” you raise your arms and legs, bring up your chest and last your hips off the ground. It is easy to do once you practice this wave slowly a few times. do it according to your breath and it will be come fun. 

To learn to use your arms and legs better it is best to first keep them out of the way. Roll on the ground using your legs and torso, your head (the body follows the eyes) and keep the arms from entangling or acting as stops. Once you can do this easily try to use the arms as pivots (for example you can put one arm across the back and create a roll to one side instead of a backwards roll)  

take a piece of rope about twice the length of your arm and tie it to a circle. Now start rotating it fast over one finger and slow down and back to fast without stopping. Add a finger and move it up the arm and down as it turns. See how you can move the arms from the core and try it with the legs and if you can with the torso and head/neck as well. Use common sense to see how much and what type of rope is best. Have fun and play with your kids if you have any. To add a more imidiate combative aspect you can tie a small piece of metal and see what you can do with it or use the rope for trapping or deflecting and scaring (a fast rope to the eye is like a whip) and so on. Put in on your body (in the belt loops of your pants for example) and see how you draw it and use it from there. Again, have fun and remember that we learn one way and work another with the same intention and a different objective.