Just don't do anything stupid like blow your roll on -EV games (unless it's PartyPoker Sidebets, thoses rule).

I know that an downswing will make some people tilt even if it's only a little bit. Just remember that. Once negative emotions start affecting your play, just take a break.

I'm not sure how long you've been playing, but I think experiencing downswings and observing how you react is a good thing. The next time the downswing happens, it won't be as painful and you'll realize how stupid you were acting.

I don't play live, so I can only imagine how bad a live 10k+ hands downswing can be.