PLAN, PLAN, PLAN!!
Gosh! I cannot say that enough. Know what you want before you talk to someone about building your home. Why waste his time with trivial matters that you can have determined before you get to his office.
I don't expect everyone to have the exact pieces of furniture selected but you must know what kind of windows, doors, siding/brick or stone, block foundation or poured concrete, slab or basement/crawlspace, roofing type and color, drywall interior, floor covering, bathroom and kitchen fixtures, cabinets, type of interior doors, do you need appliances included, paint colors, air-conditioning and heating, electric needs as well as light fixtures.
Exterior landscaping is covered elsewhere.
If I can be of any further help just E-MAIL