Be sure to tell your designer what your budget is; costs can range from a few thousand to a few hundred thousand dollars. Your designer can't give good advice if she doesn't know your budget.

Show her what you like - pictures are the greatest shortcut there is.

Be prepared to change your mind. You're bound to learn things you don't know - and things you don't want to know, like how much some things really cost and how long the job may really take.

Be prepared to change your tastes. Designers come into your project with a fresh viewpoint and (hopefully) a lot of knowledge; until you start writing checks, let yourself play around with ideas.

Take your time. Nothing about this process is fast, from design to completion. The more legwork and study you do, the better (and less expensive) it will be in the end.

Put function over form. If the kitchen doesn't work well for you, you won't care how pretty it is when you have to avoid obstacles simply to boil water.

Expect to get several drafts of a plan. The number of drafts should be determined, at least roughly, before you sign a contract.

Expect to get plans that contain both a "plan view" (looking from the ceiling down), and "elevations" (looking straight on). Plans should include locations of doors and windows. You can't get prices for the work without a plan.

Once you have a plan, stick with it. Every change - even a minor one - is an expense and a delay.