If you live in a part of the country that allows for it, try to have the construction done during the traditionally slower building times of the year. It helps the contractor keep his subcontractors busier throughout the year, and you may find subs scheduling to be less of a hassle then if you and 50 other houses are going up at the same time. You may even be able to save some significant funds with this approach.
Go in with a REALISTIC idea of what it will cost for what level of finish you want. If you realize that what you want can't be built for less than $90/sq.ft // $100/sq.ft. // $120/sq.ft (or whatever your budget will be), then swallow that pill sooner rather than later. It will save you lots of worry & headache. If you know what the actual price of 'x' is, you can be in a better arguing position if worse comes to worse. Try to be flexible. Prices of steel and plastics products are very, very volatile right now - if the contractor can buy your steel or lumber package earlier and store it for later installation at a $10k savings to you, be prepared to go with it financially.
- Architect advertisement ahead -
Have more than just a floor plan and some sample elevations drawn - especially if you want anything much more than a 'basic' home. Spending $2000 to $4000 on a $200,000 home toward a design professional fee will probably get you much bigger dividends at the end of the process than the initial fee cost, especially with construction changes. The 'done on the back of a napkin' design or (even worse) canned design book plans (with "just these few little modifications") make some less-than-legitimate contractors salivate. Worst case, they KNOW beforehand that some (most?) major things haven't even been considered and could take advantage of your situation. In the best of circumstances a builder will high-ball their estimate to give themselves some wiggle room, especially it it appears potentially costly (for them) decisions have yet to be made by the wannabe homeowner. With a basic set of plans they can sharpen their pencils and give you a much more accurate price (usually).
Municipalities are getting more and more sophisticated with hosuing (zoning restrictions, design review boards, permitting processes, etc.) that you may find it prudent to consider an architect. You will usually be better protected legally if things should go south. Inspectors would rather go out to a jobsite with an actual set of plans to compare what's been built versus what should have been...
It doesn't HAVE to be very expensive - a lot of young, unlicensed intern (or recently-licensed) architects 'moonlight' by doing projects on the side (I was guilty of it in my not-so-distant past). Some architectural firms allow their employees this sort of experience. Depending on the size of the house and your location (here in TN it's pretty much any single-family residence less than 10,000sq.ft.), the drawings probably may not need to be stamped by a licensed professional. If you choose to go this route, be comfortable with who you select. It does not have to be an adversarial relationship.
I'm really expected to get flamed by just about any other practicing architect reading this. For any flamers, I can describe in exhaustive detail how my firm handles this sort of project.
- End of architect advertisement -
Be flexible with your personal planning & finances. Don't give yourself two days move-in time if it will actually take three days to do it right.
Be comfortable in your choice of a builder/contractor. It does NOT have to be an adversarial relationship. You will find that changes & scheduling problems go better if everyone understands & RESPECTS everybody else before the proverbial cr@p hits the proverbial fan.
If you're building for retirement - consider aging-in-place design decisions. Every day-to-day function on the same floor, minimize stairs, plan for wider doors & grab-bar installation...