I can only help you with the keyboard/mouse method (which I'm sure some people will laugh at me for using, but oh well!), it will probably be different with a game controller thingy or if you like to use macros. Sorry if this is either too obvious or useless to your gameplay setup, but figured I might as well try to help.

1. Hit F8 to target the nearest mob, or click on it.
2. Hit enter, and your action bar will appear on the screen.
3. Click the ability you want to use. You may have to select the target you wish to use it on or toggle AOE on/off and then hit enter. Instead of clicking you can also hit the corresponding number on your keyboard (the number that corresponds to its spot on your bar).

If an ability can't be used at the moment (ex: you don't have enough TP) it will be grayed out on your action bar, and if there is a cooldown timer than it will be shown there as well.

Can't help you with the archer stuff, never played that class, sorry.

Regarding moving around, it can sometimes help you avoid attacks depending on the mob. For example:
- when moles do their burrowing thing you can run away to avoid getting hit when they come up
- if you stand to the side of a puk then you won't get hit with their backflip attack thingy
- after a gnat does its teleport move, be sure not to stand in front of it so you don't get hit
- don't stand right in front of or behind raptors (breath + tail)

Oh yes, and kind of random, but try not to use weapon skills on djiggas/chigoes (the bugs!). ^^

Hope that was at least a little helpful, and good luck!