There are alot of factors that play into the data speeds, so its kind of hard to pinpoint one that will help you enhance your speed. Your locations, the building you are in, etc. I have also heard that the accuracy of the speedtests can be pretty questionable.
I've been prety happy using my EVO to teather to my laptop. I use Sprints Wireless HotSpot on my EVO, and it works great. I'm in my apartment just north of Phoenix now and this is what I got on a couple tests using speakeasy.net/speedtest on Sprints 3G:
Last Result:
Download Speed: 1930 kbps (241.3 KB/sec transfer rate)
Upload Speed: 479 kbps (59.9 KB/sec transfer rate
Last Result:
Download Speed: 2231 kbps (278.9 KB/sec transfer rate)
Upload Speed: 593 kbps (74.1 KB/sec transfer rate)