Well, I think you should start by dealing with any unresolved issues you have with your ex in your own way. Talk to someone you trust and bring out the true feelings that you have about the situation. This will be a good start for the healing process. The next step is to pre-occupy yourself with hobbies and other activities that will keep your mind off your ex.
Throw your phone into a wall until it smashes, Just Kidding. Hang out with friends or family to keep your mind off him or do fun activities until you just forget about him but this process might take a while not just a day or two.
I know this is hard, you need to delete everything. His phone number, Facebook, etc. When you feel the need to call him try doing something else. Call a friend, go for a run, play with puppies lol. Keep your mind busy!