There's some great advice in this thread (especially mine
) but I disagree with SmartSuccess on one point:
Don't try to save yourself pains and heartbreak in advance.
Firstly, it has to undermine the relationship if you hold part of yourself back like that.
Secondly, some pain is good for you - it makes you stronger. It's powerful to know you're strong enough to survive whatever comes so you can give fully of yourself to a relationship; and that only comes with experience.
You're 20. If I were your age again, I'd definately play it considerably less
safe and take more romantic chances.
Along that line of thought, noone's yet given the obvious answer to your question - if you meet someone and aren't sure if they're interested, instead of just imagining that they might be, find out by asking them to hang out for a bit, or whatever!
I don't agree with everything the PUA's say but "be willing to try and fail" is as good advice here as it is in most of life...