It’s true, we are naturally attracted to people like ourselves. The more you have in common the better but even more important, you should show him your interest by mirroring him. This doesn’t necessarily mean you’ve got to wear the same clothes as he does. However you should copy his actions. If he takes a sip of his drink you should do the same. Use the same words he does later in the conversation, and if he holds his hands a certain way you should do the same.
Plus, it gives you the time to get past the initial unbearable phase of missing him and into a more even-tempered, secure mentality. Instead of trying to figure out signs your ex still loves you, you’ll be working on yourself and getting yourself into a better mindset. It gives you the space to say, “I don’t need him to be happy – I can be happy all on my own”.