[u][b]Dealing with Rejection[/b][/u]
You're going to be rejected more often than not, most likely, if you are constantly trying to join RPs.  Lots of people have preferred groups they enjoy RPing with and it can be hard to get into one of those groups sometimes.  Even if you are friends with a group here RPs often only really have so many slots for characters before they become unwieldy.  It may come down to "We like you and we like your character but BangoSkank is just so much better and his character is a work of art so we're going with him."

That is a common problem here.  Try not to take it personally.

[u][b]My RP Died Before It Ended[/b][/u]
RPs almost never live long enough to properly finish.  It happens sometimes but that is the exception rather than the rule.  If you have participated in an RP from it's birth through it's awkward teenage years and then to a satisfying conclusion Congratulations.  If you haven't try to understand that that is the norm.  People lose interest, life intervenes, inspiration waxes and wanes, and sometimes people just have the attention spans of goldfish and attach to a new RP.  It doesn't mean you're a bad writer, it doesn't mean they're bad writers, it doesn't mean anyone is a dick, it's just how this hobby goes.