This is figuring you are out of it already. This won't be easy. Here are a few steps.
If you have any of their stuff, throw it out or box it up and put it where you won't look at it. This includes valuable presents like jewelry, watches, clothes.
Get rid of their phone number, block their screen name, delete their email addresses.
The idea is if you see stuff that reminds you of them it will take longer to move on to a good and healthy relationship.
Get involved with something to keep your mind busy and where you could meet new people. If you are too busy you won't think of them as much and the next thing you will know you will be moved on. Get involved with a church, sporting team, hobby, going to the gym, etc.
You just need time to get over it and you need to put yourself in a position where you will find someone it will be a good relationship with.