Rough Edges

Hi
I am always having problems with really rough edges when designing interfaces etc.
I have tried loading the selections, contracting by 1 or 2 pixels, inverting the selection and pressing delete but this doesn't seem to be as effective as i would like.
I see some designers have perfectcly smooth edges but I can never seem to get it quite right.
Is there a more effective method?
I use Photoshop 6

certain curves wouldn't have a smooth look than others, mainly because of it's angle. if you're getting problems with jagged edges, check to see if you have Anti-aliasing checked.

Too easy
Thankyou for that