As I read through the comments made by others I really think Deb Lecours and Michael Young had great advice. To expand on their thoughts. As Deb points out, be your own purchasing agent. Spend a few weeks or better yet months visiting kitchen design centers with a simple floor plan of your kitchen. Consider this time part of your education about all of things inside a kitchen you never knew. Choose everything from cabinets and counter tops, kitchen sink, faucet, all the appliances, light fixtures, flooring, and on and on. Have lower cost alternates if the final budget grows too high. Figure all of the items you price are plus or minus half your budget. Know the lead time to delivery on all items. Organize it onto a spread sheet for the contractors you interview. Remember the contractor is interviewing you. The more organized and decisive you present yourself and your project, the easier it is for me to cut down on my projected costs.
I disagree will Michael on only one small point. When he says, "It's almost a full-time job just managing the contractors and laborers". Actually it is more than full time job for me. But then contractors like myself also manage clients, architects, and suppliers. I think when consumers act as their own general contractors the quote they get from specialty contractors (plumbing, electrical, tile, ect) is higher than I would receive for the same job. Their concern is that they will need to spend extra time educating you as to their requirements.
Owner: House to Home Remodeling
In closing organization prior to and during your project is the best way to bring it in on budget. Increasing general contractors are willing to work with their clients who wish to assume responsibility and take over functions to save money. Make that part of your bid requirements. Present your project as thought through and organized and it will show up in the quotes you receive.