Here have some steps to make peace with her/him :
Leave him/her alone for a while.
Call him/her when you're relatively certain that both of you have had ample time to cool off/
Be sincere and humble. Apologize for your role in the fight.
Make sure to listen carefully to what your friend says. Ready body language and make sure your body language isn't communicating something you don't intend. Situations may not have been as they appeared and there's always room to learn
Do not leave issues unresolved but at the same time know when to take a break. Don't keep pushing for a resolution if its obvious that your friend isn't interested in one. Find a temporary solution and resolve the issue later.
Try to lay low for a while, don't start any gossip or anything and DO NOT GET INVOLVED with any fights or rumors that could damage this friendship more then it is.
Also be aware that giving someone time isn't always the best solution/
All the best... enjoy....lolz!