Many dating and relationship experts say use the no contact rule to get an ex back. Which means after the break up, you do not contact your ex what so ever. Use this time to heal the pain and heartarche, making yourself a better person, hanging out with friends, taking up activities, date other people, concentrate on work, and spend time with your family.
The no contact rule can make an ex miss you and realise what they have lost, or realise what a mistake they made in breaking up the relationship.
The no contact rule also helps you heal and move on. In fact that is the rules main purpose.
So even if your ex does not come back, you can easily move on cause you have been in no contact and have healed and got over the break up.