If love was once there then the possibility for it still being there may be real. You may not be able to turn back the clock or make the mistakes disappear but you can give that love another chance to live again. If you have both been able to step back away from the mistake(s) and have been given enough time to breathe you may be able to come back together just to talk. You won't want to rush right back into it though.
There were problems that interrupted the romance. You need to make sure that you are able to move past it and have any unresolved issues resolved. How can you think about starting where you left off if where you left off was a bad place. Work through the problems. If you can't then you won't be able to get back with your ex boyfriend or girlfriend for very long.
The break up may have happened because of one event. It could have been because of that one behavior that one of you couldn't handle the other doing. Whatever the problem was you need to find out how to either accept deal with the problem or find out how it can be fixed.
If the issue was one cheating on the other, that may be hard to overcome. Trust has been broken and getting that trust back will be difficult. Overcoming a heartbreak because of that is difficult and it needs to be given both time and a reason to believe that there can be trust again. This is an area that marriage counseling or other type of couple's therapy can be helpful.
It is important not to come across as needy. You may feel desperate to get them back but this will only be seen as something that will give your ex power over you. You need to seem confident and that you are OK with yourself. The more confident you feel, the more likely they are going to be impressed with you and find you attractive once again.
Always ask yourself if this is the right thing to do. Make sure that you are going to be better off with them than you are without them. If it is only going to turn bad again then all your work trying to figure out how to get back with your ex will have been in vain.
Learn more in The Magic Of Making Up