Just studying the Ruy Lopez opening and its variations. I tried playing chess on Android and it was hard going. I lost. But it was easier after I disabled the program’s openings book. So a good opening move can be important.
My style of play, learned from childhood without studying any books, seems to be “blow a hole in the centre with some pawn gambit and let the knights and bishops move”. Easy to cripple by simply locking the pawns, if the opponent is competent to any degree.
Upon study, my opening looks like a botched Ruy Lopez, with the bishop half heartedly moving less than halfway and me trying to act entirely from the centre with a pawn gambit.
I’ll also look into the King’s Indian attack, which is a pretty rigid set of moves. Just these two to start with.