[Toa Circuit]

Granted most of our girls are homeschooled and thus really aren't exposed to a lot of stereotypes/don't care at all about peer pressure...
You get them the same way you get other students: word of mouth. Don't treat them different. Affirmative action style programming makes people feel like they're getting on the team because they're a minority, not because they have actual value they can give to the team.

You get more girls the same way you get more boys. Have a solid outreach program that isn't exclusionary, and have a solid team that isn't exclusionary. Don't divide people up into groups. That's all.

Granted, yes, you're going to have to treat all individuals differently, and yes, that means you may end up being more emotionally sensitive to the girls and more factual to the guys. (Of course there's cases where the reverse is very much true)

TL;DR: People are individuals, not collectives; treat them as such!