So I've just recently started to get into making single player replays but every time i make one i notice it looks either ridiculously spastic or even when its somewhat good its looks stiff awkward looking. any tips?

relax all and try to be more fluidic
requires practice
and also first decide what you really want to do in your replay and then try to make it or you will end up with something stupid
if you don't know what to do then try random things and you will be surely get an idea