You can cut as much or as little as you want. I was kind of limited by the lettering, but I've still got a bit of a flashdance vibe going on now. Try your best to keep the line smooth, and cut off any excess jagged bits. Don't forget that old saying: Measure twice, cut once!
If you've got some killer abs, chop the shit out of it. I don't have killer abs at all, so I cut just above the hem so the whole look would be a bit more uniform.
TA DAH! So simple, right? Start to finish this probably took me all of five minutes and I'm a million times happier with the shirt now. It doesn't look like I stole it from a little boy anymore! Let's be honest, only Megan Fox can really get away with that look.