Having just gone through the process of building a custom-built house and still not QUITE through the entire process, a few observations:
Plan on it taking twice as long as you think. We bought a piece of property, privately-owned, and it took over 5 MONTHS to get the permits in St. Mary's. Also, from the time I first contacted the land-owner about the property, to buying the property, finding a builder, getting permits, and actual construction, it has been TWO years. It may be less if you're building in a subdivision, but it ALWAYS takes longer than you think and they tell you.
Ask everyone you know about builders - recommendations of who's good and not good - select three or more that are promising, and sit down with them individually for a couple of hours to go over what you're looking for. Get estimates from each one and make sure you go over in detail what they're proposing. We talked to 5 builders and interviewed three in detail. We didn't select the one with the cheapest price - we had several recommendations from friends on this builder and actually went to some of his building sites to see the type of work they do. He was the most willing to work with us and responsive to our calls. He has been that way the entire process and we have had very little problems with him.
Be involved every step of the way and make sure you have good communication with your builder. Go to the job site and do your own inspections. Be a pain in the a$$
- speak up - it's YOUR home and YOUR money. Talk to your builder frequently, if just to get an update - they don't always remember to tell you something. If something is unacceptable, make them do it over until they get it right. We found our builder had framed the house in 2 X 4 when we specified 2 X 6 construction - they did it over.
Don't be afraid to bring ideas to your builder. Along the way, you find some things work and others don't - talk it over and see if it can be done your way. We added a powder room and modified some of the basic floor plan because it worked better for us.
Know your rights when building a house. On the link Barbra posted,
http://www.oag.state.md.us/Homebuilder/index.htm, is a booklet entitled "Buying a New Home: Consumer Rights and Remedies Under Maryland Law" - very good information. Read and re-read it several times - your builder is also required to give you a copy of it at the time you sign the contract.
These are the major points I can think of now, but I'm sure others can add to it. Hope it helps.