I'm not feeling well today, so please bear with me as I try to work through this. I'm hesitant to say too much about the Elliot Rodgers massacre because I know so little about it and I don't want to be one of those people that sees a tragedy and immediately claims with certainty that the cause of the tragedy was whatever axe the writer has to grind.
Obviously, I wasn't Elliot Rodgers or anything like him. I will say, though,that there are aspects of the story that sound uncomfortably familiar to me. At Elliot's age, I too was awkward, single, and miserable about being both of those. I felt I was "friend zoned" before that was a common expression, that women always went for guys who were jerks, and that there must have been something wrong with me because being "who I was" wasn't working. It was a pretty lousy time, and I suspect it was a pretty lousy time to be the object of my affection as well.
So, what I'd like to do is to try to lay out the advice I wish I'd been given (or, rather, wish I'd had the wisdom to hear). This may not paint me in the most flattering light; hindsight may be accurate, but it isn't always fun.
The first thing I'd say is to be honest about your intentions. If you're romantically interested in a woman, don't try to hide that from her. Back when I was your age (or, in this case, you), I'd get a crush on a woman and try to be so good to her that she'd just fall in love with me. That way, I didn't have to put myself out there if she didn't feel the same way. Of course, it also meant that she has no clue how I felt. I was building up this relationship up in my head, making it a huge thing that would break me in two when it didn't work out.
It was a bullshit thing to do. While I was busy trying to be super nice, some other guy would actually ask her out and she would often go along with it. I felt so betrayed, as if she was rejecting me. In reality, I'd never even taken the first step of letting her know I was interested. So, seriously, that's step one: Be honest. She deserves the opportunity to respond to your true intentions.
The second one is tougher because it's a lot easier to see in the rear view mirror: Rejection isn't the end of the world. It only seemed like it because it the entire relationship was taking place in my head. It's so much less painful if you're up-front. I've managed to remain friends with plenty of women who weren't interested in dating me because we started out from an place of honesty. Once they decided they weren't interested, then I could choose to either be friends, or if I felt I couldn't do that, then cut things off.
The next one is related to that last: If she says she's not interested, respect that. Don't pretend to be a friend while harboring a secret crush. Either be a real friend or get out of Dodge. This one's much, much harder than it sounds, and I'm not going to pretend like I've ever completely mastered it, but it will save everyone involved a lot of heartache.
This is probably something that needs to be said to all teens and twenty-somethings, and they probably won't really take it to heart, but here goes: You are not alone. There's nothing unique about your awkwardness, your loneliness, your sense that something's "wrong" with you. Maybe the existence of the internet alleviates this a little, maybe not. But no matter how utterly alone you feel, and you will feel that way sometimes, it isn't just you who is struggling with these things.
Finally, and I'm embarrassed to have to bring this up, but there is no method, no trick, no magic to getting a woman interested. Manipulation is no way to start a relationship, and it's a horrible, disrespectful way to treat someone. Even if it worked (and thank goodness it doesn't), that's not how you treat someone you want to have as your partner.
In short, she's not with the other guy because he's a jerk and she's not rejecting you because you're too "nice." I get where that internal narrative comes from, but it's a fantasy I created to try to make sense of a lot of frustration. I really do get it. But it's not true, and a huge source of your disappointment is due to looking at it through this lens. She's her own person, and if you don't treat like one, you're going to be miserable for a long time.