Know what to ask designers. You need to talk to these people before you choose one to work with and asking the right questions can make all the difference in the world. You need to find out how long they've been in the business of designing home plans, what they have done in the past, and see what they can do for you. Make sure you look at a collection of other houses they have designed; this will give you a solid idea of the quality of their workmanship and creative talent.
Ranch style architecture originated in the United States in the 1920's, and it became very popular after World War II as cities expanded into suburbs and inexpensive tract homes were needed by a growing populace. Ranch style houses are most popular where land is inexpensive and the weather is mild, since these homes particularly lend themselves to outdoor living. The low, earth hugging look with clean, modern lines of the ranch style is derived from Frank Lloyd Wright's prairie style architecture.
A few questions you will need to answer will include: how many bedrooms, whether or not to have a family room, if a separate study room is valuable, and if internal garage access will be important. Plans come in both 2D and 3D versions for you to review before building begins. You will want to go over these with a fine toothed comb, as changes are much easier to make on the blue prints then once actually constructed on the ground.
Look for reputable designers. There are hundreds of different builders out there and every single one has a different history and reputation within the community. If you take the time to check out all of the available designers, you should have no trouble finding the best in the industry.