Not sure if you all are being serious or not, but I think the best way to get a girlfriend is to not worry about girls. It's a pretty common statement, but most girls have TONS of guys approaching them so they're used to being, I guess 'hit on', pretty frequently. I know there are some guys who wish they had the confidence to go out there and compliment every girl they walk past, but the truth is if you have time to do that so frequently, then I imagine that the women you're trying to gain the attention of sees that you don't have much going on for yourself. I'm not saying anyone here does that, but from me observing my surroundings everyday I see this happen quite often. Become the best you can be and always try to show your best efforts. That way you won't have to do all the chasing...I will admit however, it's always best to get the practice of socializing with people you find attractive and who catch your interest, and it doesn't always have to be someone you have to try dating.
A wise comedian once said, "You don't wait for the one, You practice for the one." It has multiple uses of course, but for this moment it's more on socializing.
I may not have ever had a girlfriend in the past, but that doesn't mean I've never had the opportunity. And I'm better at making friends than I'd like to believe.
By the way ignore Pick-ups Artists, those guys will steer you in the wrong direction.