Reconciliation after a breakup is not an easy task but it is do-able.
A breakup is not an irrevocable situation.
Something could be done about it if you truly set your mind.
However, reconciling with a person who has moved on might be tough, but possible.
Here are some tips for reference.
Why did you breakup? - Who did the breaking up? If you were dumped by your ex he or she might have a legitimate reason for doing it.
Look and study closely the events that led up to the breakup.
If you think it was your fault, have the courage to say you are sorry.
Admit your fault and if your ex has some decency, he or she would have to admit some shortcomings too.
If your ex does not admit any error and seem to be condescending about it, then it would be better if you run away from him or her as fast as you can.
Stay calm - In other words, play it cool.
Once you have sort out the root cause of the breakup, keep to your side and play it by ear.
If you think your ex is on the move to get back you, leave the door open but not wide open.
Save room for a little "playing hard to get" mode to add spice to the stale relationship.
Change for the better - It does not matter if you and your ex get back together or not.
The more important thing is for you to realize your shortcomings and make an effort to improve yourself.
If your teeth are crooked, have them fixed if you can afford it.
If you have a bad temper, work on it.
You yourself will be amazed by the new you.
Move on - Answer in all honesty.
Do you really want your ex back in spite of all the hurt he/she has caused you? Move on...