Hmm....now that is a debate best left well alone... Personally I prefer keyboard and mouse, mostly because it's what I'm most used to but I've also read somewhere that better accuracy is attained with this kind of set up..
If your playing a game like Call of Duty (C.O.D.), a FPS (first person shooter) then you'll be using the classic k'board and mouse set up.
This usually entails that the keys W,A,S,D are used for forwards, backwards, left and right with the mouse taking care of your visual movement as well as any firing/attacking that has to be done.. Anything else is taken care of by extra keys assigned on the keyboard or mouse.
At first, especially if you've never tried it before, it can take a while to get used to. Being able to syncronise the movement between the mouse and the keyboard does become a bit of an art but with practise and a game that you like it soon becomes easy.
I cannot stress this enough though, you've got to be playing something that you really want to play otherwise you won't have the heart in it and after multiple deaths you may find yourself losing heart and just giving up. I suggest downloading a few demo's. If you don't like the look or the feel, just move on. Find one that you really want to play and then study the controls section. You'll usually find this in the games options. In fact many games do come with a tutorial feature which are worth checking out..
I'm trying to think of some good demo's:
Here's a good game that'll have a few scares too:
Demo Versions: FEAR Single-Player Demo - Demo Movie Patch Download Section - GamersHell.com I'm currently playing it's next episode and they are truly awesome games.. Anyhow here's another:
Demo Versions: BioShock Demo - Demo Movie Patch Download Section - GamersHell.com Another tip is wait until the game has started and if possible find somewhere quite and just practice moving around.. Usually in games the first levels are pretty tame so you should be able to sneak off easy enough..
This may also help:
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