Game-Play advice

The number 1 tip, is to keep an eye on your accuracy meter (the bar to the left of your screen)
moving, turning fast, jumping, firing repeatedly, will all decrease your accuracy.. if the bar is small and green, your next shot will be fairly accurate
If the bar is long & red, your next shot will be very in-accurate.
When you crouch your accuracy will return faster compared than when your standing.

Use the right weapon for the right situation.. pistols close to mid range, rifles mid to long range.. musket for long to very long range.

Use your walk button, or crouch if you want to move silently, sneaking up on an unsuspecting enemy is very rewarding :)
When walking, doors will open silently.

Finally, WildWest is a team-game, and so you should think of your team-mates before doing anything in-game, If your a Doctor, hang back from the front line, and come in to revive / heal when needed... Sherrifs & Captains: keep your team-mates well stocked with ammo (don't wait to be asked for ammo).. All players should be helping the Miner blow the objective, either by creating diversions, or clearing out the enemy for him....
Use the Team-chat to communicate your intentions (don't do global chat or the enemy will read your intentions, although this can be a good way to fool them ;) )