there's no more to say than that: "paly with connection settings" and also (ant that is in the wiki too) "reload your patience" ;-)
take a look at what credits are (in the FAQ too). the ed2k network is designed to prevent clients from leeching, so there's no way you can get better download speeds than what you get :-P Only way: Gain credits, set your preferences connections to whatever fits better to you.
what are the best settings yuo can get for your connection? you are the only one who can now. depends on connection type, ISP, modem/router/whatever, status of the lines, and so many other things...
Greetings!