hey i got my compressor today which is a marshall ED-1 and ha a play around with it earlier, at first i had it as the first thing in my line of pedals (guitar>comp>distortion>wah>amp)

and i wasnt impressed at all, i just got alot off buzzing so i tohught something must be wrong.
i then moved it to the end of the line (after the wah) and i noticed and immediate difference, most probably because it is now compressing everything before it?

so i was wondering if you guys and girls have some tips for using compressors and/or favourite settings?

A compressor, as you may allready know, makes the quieter things in your signal a bit louder (and the loud things a bit quieter).
Among those "quiet things" may also be any noise you have.

Other than that the main difference is placing it before or after distortion. Placed before the distortion it flattens out the dynamics from you're playing, good for an even rythm guitar sound. At the end of your chain of pedals it just evens out the overall volume level.
cheers i looked in the book again and it says something like the attack is the amount of time it takes to compress, does these mean its sorta like how heavy the pick attack will sound?
My compressor it is a real tube thing and has four knobs: attack, sensitiveness (gain), sustain and master. And it also has an inbuilt 10 dB booster. I use it as a booster for preamp channels right after the pickups. So it goes before any pedal I use and it grows noisy if I dial its sustain or sensitiveness to maximum. I don't use it after all my other pedals because this guitar loses expressiveness and gets a bit gray. So for blueses it's just ok, it may give either good attack or long sustain or both, which will defenitely diverse your playing. As for the heavy metal things, I think it's possible to go after all your pedals in order to make your gain more viscous and not to lose tails of your sound. Sometimes compression is used when making a taperecording, but it may go even separately, after you've recorded your dry riffs.

I also own a Maxon cp 101 and it has different character. It has less features and rather smooth and counerbalanced and less noisy than the above-mentioned tube thing. To be honset, I haven't found the best way to use it yet.