here is how you practice mind games, you use every single move you have in the wierdest ways you can think of and try them against EVERY single move in the game and against every approach you can think of. Play a few thousand matches against 100+ different people or 20+ really good people.
Go to tournaments regularly learn how to do any technique you read about on the boards and see if you can get it to work for you.
Try not to misspredict people it makes you slower. Try and predict people it makes you faster. Try and be unpredictable it makes your opponent slower. Learn what things condition you, if you go for a grab and it is spot dodged and you are comboed to death it will make you grab less often, if your opponent notices this they will take advantage of what you ARE doing and you will lose worse than if you tried to grab at another unexpected time. Know that this will work against your opponent too, if you punish something very severely they are less likely to try it again right away, know this and it should help predict what they will do. If they do the same things over and over punish it until they stop.