New Online Player

There are new players from time to time that come around.  I would suggest watching a couple of replays to see what more experienced players do.  Learning what counters what is a big thing and what the races are capable of.  It is also worth noting how other players expand.  Other than that I think the best way to learn is jump right in with the experienced players and learn that way.  Watch a replay after and see what they did to beat you and try to come up with ways that you will combat it in the future.  I am guessing it was a mostly skilled game that you joined and turned you away.  It does happen from time to time as there are some less willing to risk the game actually being a 4v5 because the relative noob doesn't put up much of a fight or leaves at the drop of a hat.  At any rate, have a little patience and you will get a game.  Sometimes it takes the more well known people(me included) 30 minutes to get a game.  The best time to get games is evenings in the US or on the weekend.  Good luck and welcome to sins multiplayer.

[_]-Greyfox

When you say that you're having trouble joining games, are you receiving the dreaded Mesh error?  Do you get an error message saying, "Your Mesh Files Differ from the Host"?  That isn't hard to fix and is a bug caused by a few extra mesh files that came with Trinity.  You can find out how to fix it here:

http://TinyURL.com/Sins10

The last message in that thread might be most helpful.

On the other hand if you're talking about not being welcome at the pros' 5v5's then it's pretty much like what Greyfox said.  However, often they need players and they'll let you play.  Just let them know that you're new and willing to learn and follow people's advice.  You might have an easier time finding newer players on the original vanilla Sins (SinsOfaSolarEmpire.exe), however the people on that server normally play comp stomps and there aren't too many 3v3s, 4v4s, or 5v5s.  (Unfortunately this game just has low player counts, especially two-and-a-half years after its release.)

Anyway, I think that it's a great game and I cannot stand to play it unless I'm playing against human opponents.  I hope you feel the same way and that you are able to get up to speed quickly and enjoy playing online.  Try to keep a thick skin and view the games as learning experiences; getting beaten an dissecting replays is the only way to learn the game and improve.  Once you learn to hold your own and become more experienced you'll probably really enjoy it.