1. Make sure that you socially alienate yourself. It will allow your friends to sort of forget you exist.
2. Once they have forgotten to have any expectations from you, call or preferably text/email them. They will feel a surge of nostalgia so powerful that they will only remember you from when you used to be fun.
3. Rotate between friends and make contact with a patterned irregularity. You have to keep yourself away so that they don't realize what a bundle of joy you are (insert morose lame sarcasm) but don't completely forget about you as well. Your moroseness will force you to resort to ideological control and playing mind games.
4. Make sure you remember approximate birthdays - so that when you text them (giving them options as to when their birthday falls), they are bowled over by how much they mean to you that you remember their birthday without Facebook. This can only apply to friends you talk to on a yearly basis.
5. Hoard your stories. That will give you material to make conversation so that people still talk to you and not completely abandon you.
6. Keep your neediness in check but not so much that your friends forget how pathetically dependent you are on them. Manipulation of their better selves is key.
7. While you have become a no fun monster, your tragic flaw is that you haven't gained the insight of an introvert. You still cannot listen but because you have shut them out of your life, your snivelling tendency to be able to feel that you 'know them' will ensure your interest - thereby allowing you to be a better listener and subsequently giving your friends an intimation of your maturity and growth. The do-gooder in them will force them to not leave a promising albeit imperfect human project.
8. As you have become morose and alone, you now have the time to hoard up on random bits of news and cultural trivia - this will allow your friends to still keep you in their life as you are 'not too dumb' and sometimes interesting. Otherwise they will run for the hills because you are such a drag.
9. Develop a certain flare for invoking nostalgic memories from your times spent together so that you can guilt them into staying.
10. If all else fails, talk about how sad you really are - your friends will be afraid of karma to leave you in your days of mental breakdown even though you are acting like you are the reincarnation of Edgar Allen Poe.