"Just put yourself out there" well, this might work if someone notices and cares that you are "out there" .. wherever "there" is .. but if nobody gives a **** you're still screwed.
"Just focus on something else ...." seems to be just another way of being told you should give up.
"Fake it until you make it" except, of course, you never do make it, because you end up being branded a fake and a liar.
"You're still young ...." seems to be often said by older people who are in a relationship.
"You're lucky ...." another one that seems to be said by people who either have chosen to be single, or who aren't single, and definitely won't end their relationship.
"Just smile!" similar to the first one, in that if nobody cares it has no effect ... and in my experience, often only entices abusive comments from strangers.
"Do what makes YOU happy" well, being able to share the things I like with someone, go out with someone, and share affection and intimacy is what would make me happy .....
Plus of course the already mentioned "It will happen when you least expect it", and "You'll find someone one day ..."