Although teenagers want to spend most of the time with their friends, they often have conflicts which can ruin their friendship. It's ok to quarrel time to time, even with mates, but picking on or loosing touch for months or years is a real sign of alarm.
There are lots of reasons why teens have problems in contact with friends. That all can start from low self-esteem, for example. Actually, this problem has lots of consequences if it is missed at early times, and some of them can be larger and worse than issues with counting on. If we're talking about friendship, because of low self-esteem there are some painful problems appearing, like, for example, difficulties with just getting to know new people. As I said, it can go further.
In the sense of self-esteem, there is an advice which can be given there.
Remember that you are you. You don't have to pretend to be nice for being accepted. Just be yourself - you have lots of qualities which make you special. Not all of them are good, but it is still great that there's a unique person, you can't find another like this one. Negative qualities also make you valuable. The most important thing is to admit each one. Show people you worth all the best!
Don't be afraid of sharing yourself with others. Be opened. Try to stay relaxed, image you're determined and confident - soon you'll feel you don't have to make much effort to act free and bravely. Maybe you think it is despite the first advice, but it's not - you're doing that to feel more comfortable, not to impress others. Be yourself, but try to be a little bit more brave.
I hope this advice will help you in communication with your friends, family and other people and be useful in questions of trusting and enjoying any company you're in. I try to use it too, and it helps, so I feel really proud of myself. Sticking to these recommendations might be the first step to a better and more effective contact with everybody who's around.