I wanted to enter a NICE entry for the HA contest but no matter what I do, my image doesn't line up on the HA preview. Also, how in the ding dang world do I draw? Should I start with the big HA models and resize? Should I take a wild guess and try to get lucky? Obviously I am never going to be able to do this for anything other than a contest, but I'd like some tips please?

I know this is probably a bit late. But maybe try going here and watch the video for some tips?

I think resizing is a pretty normal technique people use, and I used to always do that with my art. As for everything else, I don't really have enough experience to know how to answer them. ^^;

You need to draw on a separate layer directly over the large HA. your program should have a "Layers" tab so just create a new one make sure it's on top of the HA and draw directly onto the HA for a perfect fit.

Once you're done resize it accordingly and it should fit perfectly. The resizing will also help make it look a bit smoother.