Best advice I can tell you Asset, is to consider getting approached a non-issue. If you get approached, great you're doing something right, but just as the hunter doesn't plan on their game running right towards them, you can't expect to be approached. It is your mission to do the approaching.
That being said, if you are observant enough, you can find a lot of things to talk about. Here are a couple of examples:
Class situation: I noticed this girl consistently sitting alone, and consistently having little snacks and drinks in class. One day, I commented "Man, you really like coming prepared to class, food and everything." She laughed and explained that she never has time to get food in between classes. Boom, conversation right there. Oh why not? Etc etc...
Concert situation: I noticed two girls getting hit on by some dudes, and they got blown out. Some guy in front of one of the girls was tall so I joked that they should get one of their guy friends to hoist them up (I said this because I knew they didn't have any guy friends with them). They said they didn't have any guy friends. From there, it's easy enough to keep the conversation going.
Later that night, I noticed these girls trying to contact their friends with the celly. They kept holding the phone up into the air, and I jokingly asked "Does it text faster when you hold it up high?" And once again, a conversation ensued.
Sometimes the conversation will die. That's okay, just let it die, you can be comfortable not having anything to say. Sometimes it's better than trying to force it. Just keep making honest efforts and you'll get better. It's like any 'skill', you have to keep using it, which sometimes means failing or tripping up. Ever bust out freestyle sessions with your friends? The only way to learn is to open up your mouth and sound like a fool for a bit. But eventually you get better and start making sense.
-----> Just do it.
I would like to add, on the topic of 'he said, she said' bullshit: I did this a lot without even realizing it. Don't get caught up with what other people say about other people. Get to know them yourself, if they're whack, they're whack, but it doesn't concern anyone else. Judge everyone based on your own personal experience with them, not off the collective experience of others. Of course, this is a balancing act, as if you know someone has a rep for being a complete ass, it's probably for good reason. But for the most part, completely disregard any of that bullshit. I can think of many times when I blew off decent girls because some other girl told me that they were bitches and crazy. In most cases, it turned out that she was a sweet girl, but just didn't know how to keep her enthusiasm under control sometimes.
You will make many more friends this way, and meet people you may have known were around. Oh, lastly, when it comes to girls do your best to remember that they are just as nervous at getting approached as you are approaching. I realize now that many times, their reactions weren't due to my lack of coolness or skill, but due to them just being nervous.