And also with a perfect complete set of your sign-up details so that when the MPAA/RIAA/analy-retentive-people-with-too-much-profit-but-still-want-more hit that tracker, they'll hand over a list with your IP and your entire download history
Personally I never use closed trackers where you have to sign up and provide an email address etc etc - for casual downloaders (NB not seeders) the normail trackers are significantly lower risk imho
On the sharing thing, it's not tied to a ratio so I just download and max out my connection and then if it's a decent release I'll stay online uploading it for as long as possible (especially if there aren't many seeds left!)