Some people just go through the "forgetting about ex" process randomly but are fortunately mentally healthy and stable (i.e. they don't treat people as sex toys and detach themselves emotionally and/or do drugs/self abuse). Long answer short it will take awhile, as it should. Here are some steps that were learned the hard way, hopefully nobody has to suffer longer than they should:
1. You got to understand that attraction is a sum game, and natural attributes (height, color, voice, etc.) score big. If you score big on the parts where you can change (personality, social status, hobbies, etc.) but aren't just the type they are attracted to naturally (I'm using that word very loosely), you will always play catch up. You shouldn't, it's supposed to be stress free and self rewarding experience.
This is really one of the right times to use "it's not me it's them". They're just that way and you are gonna have to find someone who you score big with in both categories.
2. Reminding yourself of how many times you've attracted people either passively or actively helps in discovering and believing the other important ideal, "there are other fish in the ocean".
3. Do a thorough self check, especially on the parts where you can change. Am I taking care of myself as I should? Am content with who I am as a person and don't hate myself? You can't love people or in this case encourage new people to enter your life and find something better if you are in that mental state.
4. After properly assigning the blame on them, reminding yourself it's not the end of the world and you can and will do better as you have done BEFORE, and your not hating on yourself, you can start talking to yourself about the many ways it wouldn't have worked out and that you are better off.
5. Many people who randomly go through the agonizing process also coat their ex's with this magic film called "they were perfect in every way", the smell, the way that they laugh, those small things that you incorrectly assume cannot be found elsewhere or just take too much time and luck to find them again, especially since you spent so much time adjusting to the things that are just meh or not good about them and emphasized the good parts just a tad much.
6. Finally, don't lie to yourself. In your own rating scale for relationships, it was an 8. It was great, but you did patch up the other 2 points, you got the 8 in the first place, you have faith in yourself and rationally have concluded the it's time to move on since it would have never worked and it was in no way your fault, time to block all incoming messages about this person. No more mentioning his name, no more looking at old emails and conversations, completely detatch yourself from the person in a healthy manner.
Cause some person would say "wait a sec if they don't mean anything to me then it shouldn't be a problem if I look at his profiles and messages and repeat his name...see I'm fine! I'm just testing myself over and over again!".
You probably at the height of your relationship have been mentioning his or her's name a hundred times per day, the brain makes habits, so when they are no longer there it's natural for you to be occupied by them in their absence since it became a habit.
GL.
Edit: Translated into Internet English based on Texas's request :3
