Apart from what you have already mentioned, the most important thing is that your upload speed should not be set too high. It should be about 80% of your maximum upload speed capability (remember, you need a certain amount of spare upload bandwidth to download effectively).
DSLs are quite often ADSL (asymmetric, i.e. the upload speed is not equal to the download speed, in fact, usually much lower, 256kbps and 512kbps being the norm). If in doubt, run a speed test, e.g. at speedtest.com and adjust your settings accordingly.
Remember to patch tcpip.sys and increase the limit of half-open connections to 200. And please have a good firewall and antivirus running - if your computer gets infected somehow, then adjusting the tcpip limit means that you'll be able to infect other computers that much quicker.
Also, it is unlikely that you'll get good speeds from just a few sources, so adjust your mix of rare and popular files so you have enough sources.