Instructions
Build the vehicle's base. Start with a piece 13 or 14 studs long, and widen it to four to six studs. Use narrower plates at the ends to create a basic wheel well, so the wheels don't stick out too much from the body.
Build the Hummer's interior. Put in spaces for at least four passengers, a steering wheel and the walls of the vehicle's body. If you plan to make doors that open, put the base of the hinges in now.
Attach the wheels to the front and back of the car. If you want your model to have suspension or shock absorbers, build these onto the model before installing the tires.
Build the front of the car. The Hummer's nose is typically at a slight angle. Use a hinge piece to simulate that angle. The front fenders of the car typically stick out on either side of the hood, similar to the appearance of a Jeep.
Build the rear hatch of the vehicle. On domestic Hummers, it's a boxy back end with a rear door and windows.
Build the doors, sides and roof of the car. Keep the boxy appearance of the Hummer, and add windows and a windshield.
Add accessories like a front grill bar, side mirrors and windshield wipers. The wipers on a Hummer point down from above the windshield.