I have 2 pieces of advice. One for short term. One for long term.
Short Term: Join a team. Any team is better than nothing, remember that. Make your own if you can find people as well. I'm sure there are diamonds in the rough that have no team yet.
Long Term: Only do GST with people who won't stab you in the back. This is why guilds that stay together for more than just 1 Saturday for a few hours tend to do better than guilds who just make last minute recruits in a desperate attempt to win.