For those of you who have contact with their specific person or maybe have a means of contact or have a means of seeing this person if they so chose, as in they can find out through facebook or mutual friends where their person might go out for drinks or they can see an event their person is going to or whatever it is, this is important. Run-ins are not the best thing to do after a fresh break up for sure, especially when you haven't had enough space or your emotions are still running high. After a sufficient amount of time, however, I think personally that a bit of a staged run-in isn't always the worst thing to do. There have been times where I perfectly crafted a run-in and it has led to a serious of events which won me back my person. I believe there are times where you do have to take fate into your own hands, but only when you're in the exact perfect mindset and vibration. 
After working on your overall mood/vibration for a while that you feel a new found confidence in yourself, you will find that people start to approach you more when you are out or else they receive you in a nicer way. That is because people naturally want to be close to happiness. If you can personify happiness, you will in turn attract people! It's the exact same with your specific person. Reaching a stage where you can literally shine with happiness and joy is the absolute goal because this is the flame that all the moths want to go to. There are people who are half happy, who might give a smile now and then, but they still harbour and inner sadness and they can't attract people. Some fictional people who embody happiness and are attractive because of it include Serena from Gossip Girl, Carrie from Sex and the City, Elle from Legally Blonde, plenty of Marilyn Monroe's characters, Mary from There's Something about Mary, Jennifer Lawrence and Rachel from Friends. For men, I would say Liam Hemsworth's natural personality is quite happy and relaxed which is extremely attractive to women. 

The thing is, not many people are actually naturally happy. Not many people walk into a room and light it up but we are all capable of it. I highly reccommend practicing being happy and confident in public so that when you do get the chance to see your person, you are ready for it and you are in the absolute best place of attraction. It's really not that hard to be a dream boy or girl, yet so many people don't seem to reach to that level or believe they can be that attractive. All it really takes is confidence, happiness and also wearing the right clothes and being in a good enough shape but nothing too extreme. It's mostly about how you are and how you feel about yourself and the amount of fun you're having that causes men and women to take notice and want to be near you, and your person, if they are an ex or not, are still people and will feel the same way about you as a stranger if you come across this way It's pretty much irresistible !