How do you use your Wacom tablet?

[Bacalhau]

Hello!
I own a Wacom Bamboo tablet and I put it between me and my laptop on my desk.
In Photoshop, my lines and circles are very wobbly... I have tried other softwares and the results are the same.
I noticed that I only use my fingers to move the stylus. 
I draw very slowly every attempt of line or circle as I do with paper and pencil but the results are crap (digitally).

So, title: 
How to you use your Wacom tablet? 
What is the position of your body/arm in relation of your tablet/screen?

Thanks in advance!