SOLDIERX.COM Nobody Can Stop Information Insemination

Ok I know this is kind off the typical sx topics but I'm new to video compression and maintaining a HD aspect. Here's what I've done:

I got a few bluray movies in my hdd (main movie only via anydvd). I converted the m2ts to mkv using Makemkv and the conversion was flawless still at a +20gb size. Then I used handbrake to try to reduce the size from a full 1080p to a 720p so I could get the file below 10gb. I have tried to contact a few uploaders from iptorrent to give me a few pointers. I'm not asking for a handout but just and idea on what I'm doing wrong cuz after I use handbrake the size drops as expected but the quality great diminishes. So I'm just curious on how the uploaders are able to create 720p videos at 3-5gb size? Thnx guys