The place to start when you are designing your dream kitchen is with a dimensional diagram of your kitchen space. On a large piece of graph paper, draw the outline of the kitchen space, including any doors or windows that you will have work around while you design your kitchen. Accurately mark where your plumbing and electrical supplies are located. You can move plumbing and electrical supply points, but this involves more time and money, and it is always easier to accommodate existing service supplies into your design, if practical.
If you choose to work with an established design company, you can gain control over your kitchen themes as well as the materials you want to be used. The only things that can limit you are the actual space of your kitchen and your creative imagination. There's no need to be completely original, because you can get ideas online as well as existing design galleries from bespoke kitchens. You can choose a design such as country, English shaker, or white modern kitchen design, and then customize the finishes, materials, and the way you want the kitchen to function.