Consider the breed of your dog. What your dog will need to have their dog house equipped with will depend largely on their breed. If your dog has long or thick hair or is a traditionally "cold weather" breed like a Malamute or a Husky, they will need less insulation from inclement weather than a smaller or shorter haired dog like a Chihuahua. If you are unsure or if your dog is a mixed breed, consult your dog's veterinarian about any special considerations that you might need to keep in mind when building a shelter.
Measure your dog. Your dog will reach an average height and weight when mature and full-grown depending on breed. Even if you are building your doghouse while your dog is a puppy, you will want to make sure that the shelter will be a comfortable size once your pet is full-grown. Determine what average size you expect your dog will be when they are an adult and build your dog house accordingly.
Make it breathe. Adequate ventilation is quite possibly the most important feature for your doghouse. Even if the house is the proper height and dimension for the size of your dog, inadequate ventilation will cause humidity to build up inside the shelter and it will uncomfortable for your furry friend. To compensate for this, consider using building materials like wood that will allow air to move more freely than aluminum or plastic. Make sure the main door to the doghouse is large and able to be left open and consider an extra window in one of the dog house's walls for extra air and light.
Keep it roomy. Your dog should have enough room in the constructed dog house to sit, stand up, and move around without being cramped or confined. Also keep in mind that your dog will probably personalize their doghouse with chew toys, sticks, food bowls or other treasured objects; make sure you leave room for these things, too.
Ensure durability. The doghouse he lives in will need to be constructed solidly enough to withstand inclement weather, as well as the playful nature of your pet for years.
How to Build a Dog House Provided by eHow.com