The first thing you need to do is plan your cabinets, plan your cabinets, and plan your cabinets - did you catch that you HAVE TO PLAN. You can not just start building cabinets. Designing and building kitchen cabinets takes a lot of time and consideration to do it right. If you are working with a new empty and open room, this helps, but most of us will be starting with a kitchen already full of cabinets - so we have to take all of the measurements available, and even draw a quick diagram of how the room is configured right now to help plan for the layout of utilities.
Get a piece of grid paper (paper with boxed on it), and do a quick drawing of the room as it is configured now. You do not have to get fancy with your drawing, just create a clean, 2-D aerial view. Draw the perimeter of your room (will probably be a square), and then Pretend you are a spider on the ceiling looking down. Mark the location of base cabinets and ceiling cabinets, the refrigerator, sink, oven and stove, windows and doors (remember to mark the direction the doors swing or slide). Try to measure these as best as you can to scale. Get a measuring tape and measure the length of the base cabinets, the appliances, and the overall area that the cabinets take up. Do the same for the ceiling cabinets. When using the grid paper, make each box equal to one foot.
Now, I recommend that you go to home centers and look at cabinets you like - then take the manufacturer brochures. That's right - take the brochures. Many of these brochures have great information on kitchen cabinet layout and design, and these can really help guide you in the initial planning of your cabinet space and functionality. If you can find the brochures with the room grid layouts - those are the best to start with!
Next take a look at the cabinet styles and layouts that you like. Look at elements like appliance size considerations, utility location considerations, features, wood grain, colors, and finish. Then look at the available door styles available. Next look at the available hardware on the cabinets - ranging from the door pulls to the hinges and drawer slides.
Take down a piece of paper and mark down everything that you like about the cabinets and features that you saw on the market. This will help you to start create parameters for the design of your own cabinets. If you are married - be sure to share this experience with your spouse so that you can agree on the final design, look, and functionality of the cabinets.
Excellent - now you have a much better idea for the types of cabinet styles available, doors available, hardware features that you want, and the functionality that you want from your cabinets, we can begin thinking about the room measurements and dimensions that we need to follow when installing new cabinets.
As a measurement guide, base cabinets are generally 24" deep and 36" tall (length varies). Wall cabinets are generally 12" deep, and 30-42" tall (length varies). When positioning wall cabinets above base cabinets, the minimum distance between the top of the countertop on the base cabinet and the bottom of the wall cabinet should be 18". If you are designing a kitchen island as well, you should try to keep at least 36"-48" inches of open space between the base cabinets and the kitchen island. When you design your own cabinets, you should keep these dimensions in mind to stay within building codes and functionality in the design. The dimension that you can change though is the overall length of your cabinets. This is a big advantage because stock cabinets vary in 3" increments. If you overall space need does not fit into a 3" scheme, then you can change the length of the cabinets to accommodate your space.
Custom Cabinet Design also allows you to really pay close attention to the finer details of your cabinets that are missed with stock cabinets. For example, when you design and create your own cabinets, you can butt them against the wall to avoid the need for filler strips, you can design the cabinet fronts to have only a single stile (face of the cabinet around the drawer openings) vs.. having a double wide stile that is common from screwing together two stock cabinets, and you can create a continuous toe-kick along the bottom of your cabinets.
When considering material for your cabinet construction, you can build your cabinets from solid wood available from the lumber supplier you choose to work with. Common wood species used in cabinet construction are maple, cherry, hickory, pine, and birch. I recommend that you construct the cabinet frame, doors, and drawer fronts from solid wood at a minimum. If you are going to build your own cabinets though, I would use all solid wood and avoid melamine at all costs.
Any advice after this would be getting into construction details and would be too lengthy to include in this ehow. However, I have built kitchen cabinets in the past, and have found some excellent plans that you can buy online to really help you get started and get familiar with how to construct kitchen cabinets. The website that I use for wood plans is called Plans NOW, and they have an excellent set of Kitchen cabinet plans you can purchase for a very small fee. Visit the link below to get to their site, and then search for kitchen cabinets.
Good Luck, and no one can prepare for the great feeling of satisfaction you will get from designing and constructing your own kitchen cabinets.