Before starting the battle set the Practice options to [VS CPU] and [damage display type 2 (numbers instead of the health bar)] Set the difficulty to Hard/Very Hard/Ultra Hard (whichever suits you best).
before resuming, make sure you're ready to start battling!
Then Duke it out until one of you arrives to 1000 damage received mark (or more...up to you).
Then exit and repeat. It's also a good idea to keep track of your wins/losses/total games and choosing different opponents.
Hope this helps...