Depending on the team you'll probably either end up jumping on to the whole team's training cycle, or have someone who knows what's up tell you to focus on a few things.
Coming from the perspective of a big lifter on a well known team I've seen a lot of new guys come and go - and be asked to stay the **** gone.
If you want to keep training with this team make sure that you get there a few minutes early to warm up - nobody likes to wait on anyone, especially someone with no vested interest in the team.
When you get there introduce yourself and say hi to everyone. We had a new kid come in last week who knew one of the guys, he just stared at me and the other bigger guys on our bench warming up, never said anything, and ran off after his 5 sets without saying hi or helping anyone. We all thought he was a mental midget and had no idea if he wanted to train or if one of the guys was training him as a client.
Ask questions and LISTEN - even if you don't agree. If you are hearing a bunch of crap then just don't go back, but the first day in the gym isn't the time to show off your knowledge of other people's training programs.
Spot and load for everyone - regardless of how scared you are of the weight or how tired you are.
Thank everyone for their help and keep coming back. Everyone is always looking for reliable training partners.