Here's a 100% sure success routine to having confidence with girls:
1. Go to the nearest bar.
2. Seat next to a girl.
3. Start talking with the girl, no matter what you say, or how stupid she may think you are. Oh, and smile alot.
4. Drink a beer (nothing to do with picking up girls, it's fun and you're in a damn bar

)
5. Talk to more girls.
6. Repeat this every day, you WILL get rejected ALOT! more than you think, but after less than 2 weeks you will earn the skill needed to pick up girls.
Hell, I just read it myself and it sounds stupid as fuck, but guess what- this sh*t works, better than you'd ever imagined.
Now me and my friends (that have been practising this for years) got to the point where this is as natural for us as walking in the park.
It is way easier said than done though, having the basic guts needed to start with this routine is not simple, you have to MAKE yourself approach girls, knowing you're gonna make a fool out of yourself and be rejected, sometimes in very cruel ways.

Amiok, I wish I was there to guide you through the cruel world of picking up!
Being confident in bad, however, is much harder for me, I'm still working on changing my mind state about my penis size- it's all in our heads but the head is one helluva tough organ to change!