And now to work:
A very simple drill to learn to strengthen the fingers and hands starting with walking the wall using your fingers going first side to side and than up and down and you control the tension on the fingers by how much you lean on them. Move to working of finger catching with a partner where one comes to hold you and you scissor their fingers and keep moving. Note that one finger is very easily broken or controlled and two together are much stronger so remember to keep relaxed and keep a measure of escape in your tension. Do not overextend your reach and lock yourself. This can lead to injury.