1-its really worth taking the time to visit plenty of kitchen showrooms to check out the quality of the cabinetry and design services yourself
2-check what is included-will the company you have chosen oversee the project from start to finish ? is any necessary building,plumbing and electrical work included in the quote or will you need to employ a separate builder/plumber?
3-dont agree to a quote for the design and installation of a kitchen until a designer has looked at the space . once the initial design has been completed make sure you have a full quotation for the cabinetry and installation.
4-agree a schedule of works your kitchen company to ensure all parties involved understand what has to be done and when.
5-get a written payment schedule before signing a contract and paying your deposit .