I work with architects every day. In fact, my job is to manage them and ensure that owner's goals are met! My advice, similar to Dr P and mutantcolors, let the architect do what they do. I have sat in hundreds of design meetings and despite knowing what occurs, I wouldn't try and design my own house. Design is dictated by program (in commercial), or in your case, use. A good architect will ask you questions and determine a house that fits your needs and, specifically, see the whole picture; as others have noted, orientation, flow, roof type, etc.
NOTE: I said good architect. I have many gripes with architects and so do others... which is why my profession exists, in the commercial world. Find an architect that is qualified, but also that you connect with.
- Don't draw the house in a program
- Do research ideas of what you want, floor plan wise. Ie. I want my master on the second floor near a small nursery, or I want 12 foot ceilings in one portion of the basement, with a separate air handler and structurally reinforced ceiling for my home gym.
- Don't pretend to understand code or AHJ requirements
- Do set a minimum requirement scope of work for the architect to work off of. (This is important)
- Do have an idea of finishes.
Again, the best thing you can do is just begin to think about what is important to you now, and 5-15 years in the future. Not sure where you are in life, age, family, etc. Write down things that you would like, and let the architect worry about fitting that into a floor plan. Once they get you a schematic design, agree upon direction or further refinement. Then you'll proceed to Design Development and really nail down what you want and where. Before finally moving onto construction documents that will be used to build the house.
One thing I can't state enough, to anyone engaging in construction related contracts, is have an agreed upon, clear scope of work. Also, ensure that any changes that affect scope, schedule or budget are sent in writing (email) and accepted prior to beginning work.