It's really not taht hard, just go to "connect" and try a couple of servers out, after a while you'll get a feel for which has people taht are closer, so you get better speeds.....if you want, go to dcplusplus.com (or search for DC++ on google), it's a C++ based client, which is banned by a some servers, but it's a lot easier to use, and takes up WAY less resources.
Basically share a decent amount, have usually 3 spots, and try out different servers. Me for instance, I share 80 some odd gigs, so I get into server where everybody else has craploads of stuff, makes things definetely more worthwhile.
Good luck, I kinda just figured it out for myself, I hope you can do the same.
