Measure the width of the trail or driveway you want to clear and design a snowplow that will clear as much of that width as possible in one swipe. The front of the snowplow should be shaped like a "V" with a 90-degree angle. Determine the length the boards to give you the width you need. For example, if your driveway is 10 feet wide, build a 5-foot plow that can clear it in two passes. The boards for the "V" should be about 3.5 feet long each to achieve this width.
Trim the two boards for the "V" to the length determined, and trim a third board to match the width of your plow. The fourth board will serve as a support and mounting bracket. If you plan to mount the snowplow to a vehicle, you want the board to extend from the front tip of the plow, under the vehicle and to the hitch post in the rear. For a bike-mount, this board will only need to be about 2 feet long.
Nail the "V" boards together and nail the third board to the opening of the "V" to make a triangle. Nail the fourth board to the front tip of the snowplow. If you plan to push the plow ahead of a vehicle, have the board extend from the tip and through the triangle. If you plan to pull it behind a bicycle, have the fourth board extend from the tip and away from the triangle.
Attach the small wheels to the middle of the arms of the "V," using a hammer and nails. If you will be dragging the bicycle plow, this will make it easier to move.
Nail 2-by-8-inch boards in front of the arms of the "V" to give the plow more height. These boards will move away snow up to 8 inches deep.