Did 80% of my own 1000 sq ft addition and would do it again. One heck of an experience though (and I thought I knew what I was doing/getting in to.
Just some things misc things to add:
Be sure ground passes a perk test before you buy it.
The county will probably determine where the septic tank and well need to go. I also believe they reserve a spot for a 2nd drain field if the 1st ever fails. this can severely limit where the house can go.
The guy clearing the land can cut/knock the trees down with his dozer faster than you could ever think about doing.
There may be rules on how much of the ground can be made impervious (house, asphalt/concrete drive, out building, etc.
Drill the well first since you can't really control that cost. My 150' estimated well went over 350' and that was a real shock since the house was 90% complete.
Be aware of rights of way, setback limits, etc BEFORE buying lot.
Building code is a 'minimum' to build to. Consider it a D- grade (you passed). Some things shouldn't be built to minimum.
You can probably get the drywall done faster/cheaper than if you try it yourself. Humping 12' sheets gets old in a hurry. Keep in mind there are L3, L4, L5 drywall finishes. Know the difference. The USG site has a good manual on drywalling.
Not trying to imply you can't do it, but playing GC will make you realize why a good GC gets the cut they do. Scheduling a whole house (efficiently) can be a real experience. Or having 6 framers standing around until a simple/stupid decision is made. Or 8 masons standing around with their thumb you know where while you try to get 5 more yards of sand in the next hour. Or some dick of a building inspector not likeing some stupid joist hanger that was used throughout the house. Or the wrong nails used on the hanger.
Pay attention to liability insurance and who has/needs what. You don't want to be responsible for accidents.
Understand lien lawa and how they apply to you and how to get lien releases on everything.
Don't advance any money for materials. Make sure who is responsible for materials once on site and before used and after they are used.
Who insures home while under construction? What does insuring it mean?
Understand what trades do what. For instance the framers may not do the boxing of the eaves/soffits. or who runs duct work for bathroom exhaust fans? Its probably the HVAC guy.
Be sure you are getting bids for apples vs apples and not oranges. Want #12 wire throughout? How about #14 for lighting circuits? What about 'shared neutrals' on circuits? There are all kinds of ways to meet code but it may be the D- quality I previously mentioned.
Who is responsible when the plumber hacks through walls/beams/etc and the framing inspector goes crazy?
Roof trusses? Floor trusses? Stick built? 12" 16" 24" apart? I have a CENTEX house (built to code) and every floor bounces. Drywall corners are cracking after 10 years, HVAC was done by the lowest cost moron? Again it all passed code.
Go into it with your eyes wide open, educate yourself and it can be a rewarding experience that will save you money and get you a better quality home.
Check if you can do your own electrical (if you are interested in doing it). It used to be that in Wake County you could do your own electrical. I did on my addition.
Kitchen cabinets are a whole subject by themselves. Anywhere from cheap fall apart cabinets/hardware to pay thru the nose top of the line. Same goes for plumbing fixtures and lighting. Don't forget multimedia wiring nd security.
If you are going to do your own rough plans be sure to let you friends critique them and tell you what they do/don't like. Some people even post them in forums. If you do be ready for 100
replies and 100
replies. All will be valuable. Door swings, window placements, useless hallways. inefficient kitchens/bathrooms, etc. I did my own set of house plans years ago and it took me about 6 months to get it 'right'. Luckily I had a old time builder that did me right.
Stainless steel surfaces are a real bitch to keep looking nice/clean. If the surfaces aren't kept spotless they can look awful. Be sure to talk to people that have them if that is the way you are thinking of going.
Whew.