When building or buying a home, it helps to decide just exactly what you NEED and what you WANT. Once you have a price in mind, then start looking. If you do it the other way around, you can end up falling in love with a house that you can't afford and none in your price range will compare.
Location, Location, Location
Don't you wonder why people always ask about location first? Well, it is the one thing you cannot change about the house after you buy it. However, there are things besides the neighborhood that you need to consider. Things like lot size -- do you really want 5 acres, or is it worth it to be that far from nosy neighbors.