If you are friends and have had a fight be sure to apologize for getting upset about things that aren't very important. This shows maturity, and desire to be friends.
 One great way to strengthen friendships it point out to each other how much you appreciate the friendship and then promise not to take their friendship for granted.
 Respect is huge for strengthening friendships. You need to respect each other's opinions and choices. Respect is a key ingredient in any friendship. You can't like someone you don't respect, it just doesn't work that way. With friendships, and especially when trying to strengthen friendships, one part of respecting someone is realizing that his opinions and viewpoints are just as important as your own, even if they differ.
 Tolerate and appreciate differences. We all have those little things that make us individuals, if you want to strengthen your friendships then instead of fighting about these differences you need to appreciate them. Also, understand that these things can strengthen friendships. In fact, it is our differences that make our friendships so fun!
 Flexibility in viewing situations. If you can learn to be more flexible and willing to see things from the other guy's point-of-view, you won't fight as much, and you will enjoy the time you spend together more. So, flexibility is huge in strengthening friendships. Friends should let each other have their way once in awhile. Stubbornness and inflexibility lead to too much conflict, and conflict hurts friendships.
 Listening to your friends. Even if you usually dominate the conversation, it is important to take time to listen sometimes too. When we've had a hard day, sometimes being able to talk to a friend about our feelings is all it takes to turn things around and turn stress into a feeling of connection and well-being. So, strengthen your friendships by being that person they can talk to. And don't just be there, listen as well. Having someone who will really listen to and understand us can have profound effects on us. So, give and receive supportive listening. Supportive listening means doing the following:
o Ask them about their feelings, and listen.
o Reflect back what you hear, so they know you really understand.
o Instead of always trying to tie the conversation back to your experiences, focus questions on them and their feelings.
o When they're talking, are you missing some of what they say because you're waiting for them to stop talking so you can say what you want to say next? Stop, and really listen to them.
If you can do this, you will really strengthen your friendship because they will know that it is not a competition to see who can say the most, it is genuine concern.
So, do the above things, and really just make time spent with friends enjoyable. Don't take a bunch of calls while with friends, let your focus be them. When you are with them, they should feel important, because they are. If you can do that, you won't have to worry about friendships falling apart.