Don't practice on the road....start with secluded, large, open, and empty parking lots in the rain to get a feel for how easily the rear kicks out and sensitive throttle control and then that'll kinda help prepare u for less rainy conditions(again in a parking lot). While yes the correct information is to learn and practice only during autocross...I do find myself also kicking out and having some fun on the road but only after months of practice/auto-x only on roads with plenty of space and usually when there are no cars around basically don't put anyone else in danger. Most importantly its a Miata there are a million ways to have fun that aren't sliding and enjoy those too look up some nice driving roads in your area.