OOOOOOoooooh I just thought of exactly what you need!
1) For your initial contact, write them an email and tell them how much you've missed them because they're different than everyone else. For example: You're funnier/nicer/a better listener/more fullfilling to hang out with/more fullfulling to have conversations with/have a
flavor that no one else has......etc. Basically tell them why you prefer their company over everyone else's. They'll be so flattered that someone actually
noticed!
2) Don't go overboard with the compliments, make the rest of your email normal and stuff, and then insert one really nice one. An email is perfect for this kind of thing because they won't be pressured to respond and won't be embarassed (like if you said it in real life) but it will give them time to mull this over in their head and then respond.
3) If they reply, THEN ask them if they want to hang out.
4) If they don't reply, don't give up, just follow up your email with a call asking "Hey lets go hang out on Sat at blah blah time place."
5) Don't mention your email or compliment in real life unless they bring it up, it gives it greater weight and they will be just soooooo flattered that you secretly prefer them over everyone else. They'll adore you. They'll do ANYTHING for you, because now they will put great stock in the fact that you're actually
noticing all the self-sacrificing things they're doing to get your attention/approval. So they'll do even
more!
6) Be sure to reassure them when they're doing a whole bunch of nice things for you that you just love it. Otherwise they'll worry that they're smothering you. Or they might withdraw if you're cold and unnoticing, because they're giving you their beating heart, their true feelings, and they love you so much they wonder if it's wrong to put so much trust in a fallible human.
And THAT my friend is the way to wrap an INFp around your finger. -grin-