Most people I've come across recently have had unsuccessful relationships from their long time commitment for two to five years approximately. The problem with some of the people after the break up is that they go through the lonely stage where they're seeking to replace their ex-girlfriend or boyfriend. First of all, it's never okay to immediately begin seeking another partner when you've ended it with another. The advised rule is to "Stay single for half the time you were with that person." But then again certain circumstances can change depending on whether or not you're lucky enough to find someone right for you within a shorter amount of time.
Otherwise, it's best to spend some time alone and work yourself out before you do decide to get involved with anyone else.
Rule number one after the break up...it's best not to speak to that other person for about a week or so. You or them are probably going to go through the disappointing and depressing stages before anything improves.
Rule number two...ignore all form of contact, and concentrate on how you're dealing with things rather into sinking into your usual habit of checking up on them.
Rule number three...learn to adapt to being alone, and enjoy it for a little bit. Remember, you don't have to do everything in your everyday life with someone else. It can be done alone.
Most important, rule number four. Do not date another person (within a month's time especially) or get back with your ex-girlfriend or boyfriend. If you broke up for a good reason; getting back together isn't going to solve that loneliness and the issues you might have with them.