First decide on an opening you play. Second find several games of no more than 30 moves[a great idea by our Bill Wall]. Third choose games where one side wins. Explample: I pick 50 black wins of GM strength where black won in the Petrov[my defense to e4] Finally withe the fritz 5.32 free download on this site go slowly through the moves thinking of the ideas knowing white will make a blunder but you just don't know when. Have infinite analysis on, carefully trying to catch white's mistake before making the move. Fritz will point it out for you. Choose any opening or number of games. This teaches tactics under game conditions by the best players in the world.