So I am a college junior and I have been kind of awkward I guess. There are people I pass by in the hallway who I don't talk to, even though we know each other. There are also some people who I saw many times but never introduced. This is for guys and girls.

However, now that I try to smile and talk to everybody, how do I get these people's view of me changed?

There are also some girls who I de-friended on facebook because of some emotional crap that I had before. What do I do about those people?

start talking to them.

^ Yup, start talking to them and being social.

I just finished college and I felt like I didn't even start to hit my stride socially until my senior year, so I understand where you're coming from.

In terms of your peers changing their minds about you, only they can do that if you let them see another side of you or be yourself, or at the very least, start being seen as a real person rather than just a dorm room #, face, and barely a name.

I don't know what the emotional crap you reference from before was, but if you want to repair the relationship, you should re-friend them and own up to things. Depending on the circumstance, just own up to "I lost my cool" or "I was being a bitch about XYZ when it wasn't my place." That's just my opinion though, I sincerely think people respect it when you own up to stuff and look to move past things.

Good luck!