Well i got some Ket, but i've never done it before, whats a good amount to start and a good setting to do it in?

Start with a bump. Make sure you're laying down, preferably on your back, on a hard floor with some psytrance music playing.

Also, if there's an echo in the room then it might be more interesting.

If a bump doesn't do much to you, which it probably wont, you can move it up to a smallish coke line amount.

http://www.erowid.org/chemicals/ketamine/ketamine_dose.shtml

Thanks..