Be genuine 

Being honest and genuine it may not get you a lot of friends instead, it will land you on the right ones. You should try to be genuine with your friends all the time, you don't have to be someone else just to gain a lot of friends because real buddies will give you the freedom to be yourself and accept you for whom you are. 

Find time

You Should find time and show your friends that have to be around them no matter how hard it is or how far away from each other. 

Admit and apologize 

If you have wronged, then you need to accept and apologize. In this manner the friendship will be more stronger. 

Know that there is nobody is perfect 

By realizing that there is no one is perfect will make you understand that everyone can make mistakes.