To create a conversion goal, from your "Manage" menu, click Create Conversion.
Give the goal a name. We'll call it "Sign Ups" for this example.
Select a Conversion Method. On my site, everyone who signs up for a free account is sent to a page with a URL of "/thankyou.html" after signing up. So, I use the "Path" method, and I type in "/thankyou.html".
Select a conversion value. How much is this conversion worth to you? (Info)
Set the conversion counting. Should this conversion be counted every time it happens, or only once per visitor?
Click the blue button to save.