If you have recently broken up with your ex go out to where you know they will hang out and put on that hot, red dress before you venture out for the night, even if it is to hang on the arm of your new date ie. if you wish to start attracting your ex back or at least pique their interest!
It's not fair on your new beau but if your ex still gets under your skin...? The question is, how much do you want your ex back? Enough to do whatever it takes (but play nicely and never with malice towards anyone)?
Then this is could be a winning strategy as they will still be feeling possessive towards you if your breakup is recent, enough to arouse old feelings of love, closeness, desire, etc.
And remember to smile at them, across the room, wherever they may be, even if they are with someone else. And especially if they are with someone else new!
If you don't want them to un-couple from you and even forget you then you do need to be in their face (subtly) to remind them that you are still around and looking beautiful, if you want to hook your ex back.
TIP: Be as irresistible and luscious as a ripe and juicy strawberry dangling in front of their nose (but out of reach so play it cool). Remember not to chase or hunt. On this mission your job is to leave them to go crazy with suspense over whether you have got over them or not!!