There are many ways to hook it up wrong. If it sounds good then your probably doing it right.
If you are ready to spend $500 on a mixer then I'd reccomend getting the Roland Studio Pack for $700.
It will give you a digital mixer, digital sound card and Logic Audio software. There is no better deal for the price. You can record up to 8 tracks at a time, 24 stereo tracks total. The mixer is very clean and has great built in 24bit effects.
The mackie is a great mixer but down the road you will still need a better sound card and some software.