Let's get some tips from more experienced players in here.
This first post will be modified and kept up-to-date with suggestions from the community.
This topic is under construction! More to come soon!
Quick links
Humans 
Your first purchase should usually be a helmet.
If you buy a gun but not a helmet, because "you don't have enough money", you are being a RETARD.
The bottom line is that
ANY human with Helmet + Armor + Rifle will do MORE damage than any human with an expensive gun and no armor.When you are stage 1, you should avoid buying guns if the enemies have no evolved. Rifle is a fine weapon.
When the aliens have a dragoon, buy armor to avoid getting instant-killed from pounce.To save money:
Shotgun + helmet + armor is the BEST combination for credit savings. Average goon vs this combo means the goon will die. It can also be effective against tyrants; ~3 shotgunners vs an average tyrant is a dead tyrant.
Aliens 
Building 
If the game is moving slowly and you are afraid to leave the base,
Grab a ckit and repair! When I was new at the game I knew I sucked at fighting, so I built every game. Your team can have great attackers, but as human OR alien, you are doomed without a good base. Study designs, figure out how things work, and learn from good builders. Keep in mind that most servers have around 100BP, so playing on SST will give you HORRIBLE habits.
For grangers:
Acid tube damage is based on HOW CLOSE the humans are, and has NOTHING to do with the animation! This means that acid tubes on very high ceilings are almost always bad!
Trappers have a cone-shaped line of sight. They are most effective when slightly above the door facing down, or on the wall facing sideways near foot-chest level.
Trappers can be the most important defensive structure, if used properly. Trappers are useless when placed on the floor.
For building on either team, I have found some things about good bases.
Don't block your teammates with buildables! For humans, this means making sure there is a FOOTPATH through your turrets. If your teammate has to jump, it is NOT a great design. Mostly when people run back to base they are wounded, and low on stamina. Having to wait those 1-2 seconds to refill can mean that they DIE. For aliens it means making sure that your tyrants can get anywhere inside the base to defend. An example of a bad building is a hovel on the ATCS ramp, because it makes it VERY hard for tyrants to defend the overmind!
Human and alien bases have differant strategies! For humans, you want a base that doesn't lend itself to being sniped out, and making sure that alien attack paths are well covered with damaging items. For aliens, I've found the good bases try to
slow humans down more than damage them.
Bases with one door are almost always bad. The phrase "Make your stronghold too hard to get into and you will never get out" comes to mind.
Erm... One recommandation:Newbies should not build! Get some fighting experience first to realize how the game works. Building is something quite sophisticated that requires a deeper understanding of the game, newbies should not do it. A bad base can ruin the whole game. A team full of superb players will kiss the ground goodbye when a noob places the reactor next to the entrance or moves the reactor the time the gun turrets are needed most, et cetera.
Binds
Improving as a player
Listen to players who are better than you! I can't stress this enough.
Another point I've thought of is that
you can learn from spectating good players. By doing so, you can learn their habits, movement patterns, etc.
Learning how to build makes you a better attacker. If you understand what makes a good base, you can spot the weak points of a bad base and exploit them.
Teamwork is very important in tremulous. Some might even say it's the most important.
General tips
Your base should almost ALWAYS have at least one person guarding it at all times. Sometimes this means you miss out on frontline action, but it can make the difference between losing and winning.
Communicate with your team! If your enemy has staged up, let them know. If there is a grenade, let them know so they can dodge it. If your base is being attacked, let them know.
If you are planning to move the base, let them know!Camping can be a good strategy sometimes, but if you do it ALL the time, you will lose Trem takes a balanced mix of offense and defense to win.
If you are feeding, then stay near your base instead of running out so much! 90% of the time, this is true. however, in some VERY specific cases, feeding can be a useful strategy. If you don't KNOW when it's good, don't do it.
My overall tipp to newbies (because I am one myself and learning to play the game more and more):
The amount of offensive gameplay is directly proportional to your skills.
If you know nothing, stay behind and wait for some target practise, if you start to become better, join a group of your buddies for raids, if you are a superhero, then you may lead the attack. There are also servers with bots on them. try those. If you are alien, you can learn headbites, if you are human, you can get some excellent target practise. I played about 30min today on a bot-server, then I ceased playing that "simulated game"
and joined a "real game" [oh boy, what a word
) and shot down ten dretches, where I usually shot down, erm, one or two more by accident then on purpose.
I know it seems a bit dull to put so much effort when you just want to play, want to have fun, but without any skills, you can't enjoy it, I think.
I think noobs should try all sort of things, and should do all mistakes. that's the best way to learn.
and that's why are noobs sorted if they want to play the game or leave it.
so nade base once, accidently decon reac once, feed till u get skills, get kicked occasionally, and so on. better gamers will warn you if u act stupid anyway so you can learn from them. at the same time they will promote their ars poetica also...
like if you build a trapper on floor they will laugh they ass off and yell at you so you won't do that again.
let's don't talk like there are hundred thousands of nubz out there, because they are only a small bunch of people who are playing trem. and we should keep them to make the community stronger and more fun.
To those who accuse me of being an asshole, I only do it to people who don't listen. If I'm being a dick to you, you are very likely doing something wrong. In general,
If you are polite, and ASK for help, explaining that you are new, most players will helpTerminology
Links to learn more