Ok, I just have a few tips on how NOT to be a noob, BUT I think this is a topic that everyone can feel free to add some of their tips as well. Despite the subject, this doesn't necessarily apply to noobs, a lot of it is good advice which many of you should add to. I'm not perfect, I admit that I have committed the following faults, but I'm breaking those habits.
*Don't throw smoke grenades in your own base just to find get rid of it so you can have a paint grenade, that's annoying to your teammates. While I agree that it's better to carry a paint grenade than a smoke grenade, there's a better alternative: press "6" on your keyboard. That allows you to drop it instead of initiating it, which can really piss off your teammates if it's in their base. So yes, press "6" to drop smoke nades. I great example of this is anubis, where everyone starts out in a small room that's full of grenades, it's always impossible to see in there because of noobs.
*Don't send the flag back home when it's in a more inconvenient spot to access. Ok, when I say sending the flag home, I mean touching the team flag to send it back to the base. All the time, I see someone shooting a guy with a flag in which the flag ends up in a hidden, or harder-to-get spot, and then sends it home. This shouldn't always be done, THEY KNOW when it's at the base, but if it's hidden, that makes it hard for them to grab, so don't interfere with that hiding spot. I've seen matches lost because of noobs doing this. The only time you should send it home is when it's conveniently closer to their base. This is a tough habit to break, but also a crucial habit to break, so really work on it.
*Don't send the flag home when it only moved 2 inches. I see ALL the time someone from the other team touch our flag and immediately get shot, so the flag has only moves an insignificant distance. Then some noob immediately stop what he's doing and goes and "sends the flag home". Don't do that, it makes no difference, and our team could benefit from you doing something else!