how to get a girlfriend?

Honestly It doesn't matter what you look like. Looks are very low on the "importance" scale when it comes to getting girls. It's much more about your personality and self confidence.

Try this:

Don't focus on your size or any insecurities you have. Girl's will see this lack of confidence and be turned off even at 13. Instead, you have to believe that it doesn't matter. I have friends that are total players when it comes to getting girls, and their 3 times my size. But their funny and their confident and girls like this more than anything.

FOCUS ON SOCIAL PROOF:

since your still in school make friends with everyone around you. I don't mean walk around kissing everyone's butt, instead genuinely want to become their friends. Also don't worry about it if someone doesn't want to be your friend. Not everyone is going to like you and that's just a fact of life, forget them. the reason this is so important is because in middle school, high school, and college social proof is everything. Girls are attracted to guys that other girls and guys like. It will make your job 100 times easier!

Good Luck

280lbs? geez. i hope you're really tall.