Porter,
I've ALWAYS found that successful scratchbuilding really has two major starting points.
1. Good tools.......and by this I mean real tools........good straightedges for cutting, engineers squares, clamps, a good set of vernier calipers for measuring, a scale ruler.........basically miniature engineers tools.......have a look at MicroMark - they've got some great miniature tools there.
2. Good references......if you want to copy it, you gotta be able to see what it looks like. Too many pictures is never enough.
The main thing is to try to develop good, positive, methodical modelling practices........and having an anal retentive, obsessive compulsive disorder type of personality (like I do) helps a HUGE amount.
I've found that if it's not right, it's not right. Or more accurately, close enough ISN'T good enough.
Mate, if you have any more questions or want some advice on a particular issue, just email me and I'll do my best for you.