OK, the first part is the big stuff, but there's some quick fixes at the bottom for you...
Be wary when you ask what it is that other people might find annoying about you. Pick someone you trust and only ask ONE person. I did this, with two friends. Except they weren't two friends. One was a friend and the other was the girl who resented this friendship because I was "getting in the way". They both tore shreds off me. And my crimes? I talk too much (I can babble quite well when I'm happy) And didn't display a lot of tact (I have no problem discussing fecal movements or fallacies of religion at any place or time). That was it but it was enough for them to assassinate my character.
Fair enough, I asked for it. But here are some major tips I've learned.
1. DON'T TRY TO LIVE UP TO OTHER PEOPLE'S EXPECTATIONS. Or in other words, don't spend your time trying to please everybody. Firstly you're going to be guessing what people want, so you can get it wrong. Also people are fickle, try as you might to be the person you THINK they want you to be they'll shift the goal posts. And most importantly NO ONE ASKED YOU TO NOT BE YOURSELF. If you try really hard to please people, you might actually do it, but when they show no appreciation, or grattitude for the efforts you've made you'll grow resentful. But they didn't ask you to do it so they won't feel a need to thank you.
2. BE YOURSELF, IT SAVES TIME IN THE LONG RUN - Maybe you can fake it till you make it, as they say. Behaving in a particular way until it becomes habit is normal and is part of growing up. If you take a public speaking course and learn how to present yourself, it comes off forced to begin with, but then becomes second nature after a while. It becomes part of YOU. However, if you do want to grow in this way make sure it's for YOUR purposes (i.e. remember lessong 1 above).
However, generally it's better to be yourself and get rejected. It may suck to begin with but here's the secret, most people are not going to be your best friend. Nobody is friends with everybody, and if they are they make me highly suspicious. It comes down to this, if you pretend to be somebody else then none of your friends are real friends, they're friends with fake dude. This will make you feel horrible, isolated and incongruence (look up Carl Rogerson, Unconditional Love and Congruence to get a really clear picture of what this means. Believe me, it's far better to have two friends who know you than 20 friends who think you're somebody else. They'll find out eventually and slowly they'll stop being your friends, so save yourself the time now.
3. YOU'RE NOT DONE YET - Pace yourself. You are going to make and lose friends a lot over a life time. You are going to change in how you deal with people, confidence levels with different types of people, experience, work, all these things will change you in dramatic ways. Don't get hung up on "What I'm like!" just yet. You may have beliefs and principles and ideas and they can be rock solid, that's who you are, not how you appear to others. So relax, learn from your mistakes and watch and learn. Self-awareness is hard to master but you'll get there.
QUICK FIXES
But for the quick fix just practice these things now.
1. Where are you looking when you talk to people, face, chest, away, feet. Are you too close to them, too far away. Personal space varies a lot with people, try to match the person's tone, distance, posture, eye contact, etc.
2. There's a difference between trying to please people and empathy. Trying to please people is usually someone going over board with jokes, humour, etc. Empathy is trying to understand what the other person is feeling. Focus on the person you're talking to, ask them what they're into. HERE'S THE IMPORTANT PARTS. If you don't know something they're talking about ask questions. People love to educate and explain things. They may be reluctant because they're afraid of boring people (trying to meet other people's expectations) but don't let them, try to take a real interest. It may be black and white german films and incredibly dull but what you're tying to do is find out why THEY like it, not really the subject itself. Don't lie and pretend to know stuff either, that will always backfire. Also, you might find that the one thing person wants is for you to leave them alone. Then do just that, just say "Nice talkig to you, I'll see you later" and walk off.
3. STOP! DEAD AIR IS NOT YOUR PROBLEM ALONE - I'm guessing you do what a lot of people do, get terrified when there's an awkward pause and desparately try to shovel any old crap into the conversation. DON'T, DON'T, DON'T. Either end the conversation, let them fill it in, or take a moment to think about whether you were focusing on 1 and 2 above and whether it was working.
Don't worry about fitting in. There's 7 billion people out there, we all fit in somewhere, it just might not be right where you are right now.
Good luck.
