I will present a few ideas to address this question.
First the obscure part.
You can skip straight to the movement drills and come back later for this:
Mentally we place a divider between making contact and hitting. There is no actual difference aside from that line we place before ourselves to cross.
Pushing is a drill we use to gain more self-awareness and from that we can begin to sink and move past the divide we place again all on our own between us and them.
When pushing and pulling you naturally seek the sweet spot where things move just right and you feel effortless. In sinking you remove the divides you placed and simply make contact.
Hitting is sometimes associated with causing harm and death. You can hit with that intention and as you go about that you cause harm to yourself as well as you and the other person are not as separate as you are conditioned to believe.
Hitting is also conditioned to be associated with struggle and visible effort. Simply realize that the people you are making contact with are just as fragile as you are and just as human. It will be infinitely easier to hit with compassion and as a soldier to actively defend the lives of your loved ones with no hate or tension obscuring your sight and heading.
Drills: Mind your breath. Slowly exhale as you perform a task from tying your shoe laces to writing a note. Pay attention to the tension growing naturally and note that you are in control when you keep breathing normally for what you are doing at the moment.
Hold your breath after an exhale (avoiding overpressure in the lungs) and join a partner in pushing each other until you cannot anymore. Note to move only where there is no resistance and see how you last moving whilst moving naturally instead of choosing to struggle. Flesh is fragile and non-lasting yet it shapes the continents and soars above the earth. It does so with purpose and desire. By strength and guile.
Understanding yourself gives you a window into understanding and affecting others without bringing self-harm to bear.
Start by placing yourself in just one point at the end of your fist. Place that point on the wall and keep it on that particular location. Move your elbow so your forearm moves but your fist stays where it is and see how you can sink into the wall from different location with the simple application of attention.
Now come two fists distance away from the wall and place your finger on the elbow. Avoid moving the elbow but move the fist on the wall as much as you can and see how much movement you possess when not limiting yourself to the point where you first made contact on.
Place a tennis ball or something to that fashion on the wall and move it around the wall using your fist and see how much movement you can create in another form by using all your body together.
Place yourself in the push up position and move on your fists and feet. Reverse to looking upwards on your fists and feet and again move around a bit. Now change where the movement begins to your breathing movement. Start swaying on your four limbs along with your breathing in and out and extend this inner rhythm to first small steps and then free walking from the breathing and the body to the limbs. You will be using tension to move but the right amount of tension and no more.
You can also do this on the wall depending on the mood of the day.Place your fist on a partner and repeat the drills I have already wrote down. Pay attention to your breathing and to your movement and allow the information to come to you. Otherwise you will be sucked into a loop of seeking outside guidance instead of moving from within.
Stand and have a partner hold a stick a step away from you. Have him or her swing and stab at you with the stick as you on your part keep breathing and work the movement your body already is aware of from the wall drills but with walking added. Allow the contact to come but keep moving from yourself. You may have a few bruises but the lesson will be true.
Continue this drill as you add coming into contact with your stick swinging partner and again keep breathing and paying attention. When contact is made you continue to move but here we add in inner workings to the work.
Inner workings means that people sometimes perceive the person as one homogenous being and simply press to pressure and puncture without paying attention to what the contact is relaying to them. Place your fist or finger on your person and press straight inward. Feel what the pressure creates in you and breathe.
Now press as you have moved in the wall drills and note how the tension and the different tissue in the flesh creates a dynamic and three dimensional pattern you can navigate through with more ease and connection to the whole.
Now place your fist on your partner and repeat the same drill. Bear down first and sink freely later on. Start standing or sitting and continue to walking and moving drills.
Now you are hitting with your own movement, with your own intention and with no desire to do harm.
Now your hits will be felt more than on the surface.