How do you apologise to your girlfriend?

Answertell her up front or if she won't listen, shout it out if she's ever near not caring about what anyone thinks. I mean if you really want her forgiveness you won't care what other thinks. Send her e-mails about how sorry you are. Or make her a poem saying how you regret whatever you said or/and do and that you want to start over again and that everyone deserves a second chance. but don't be all up in her face, if you think you've done everything you could (like telling everyone in your whole school that you're sorry or something that would send a message to her that you really care and that you really want her forgiveness), just give her space to think.

Tell her these Words, "I'm sorry." And mean it. The rest follows naturally. There is generally no reason to make a big show of it... some girls, you can't 'prove' to them that you're sorry. it is, to them, a matter of saying it, then discussing it.