'Don't swing so much on that volley.' What do you have an image of now? A swinging volley! Along with 'but' and 'try' let's eliminate 'don't'!! Let's start creating positive pictures and statements about what we DO want to happen. 'Don't swing' or 'shorten the swing'
'Don't set too soon' or 'connect the feet to the swing'
'Don't spill the milk' or 'keep the jug steady'
'Don't worry' or 'Have courage!' Have a great day!