First (and probably the most important), you need a level surface.
Form a frame with 2x6 boards. Here, we have 8 of them in a rectangle to make a 26'x32'frame. We dont even bother anchoring them to each other; just stand them up.
Next, we draped a 30x40' heavy duty WHITE tarp on top of the boards. Last year we used a blue tarp, which worked fine except that it was more prone to melting when the weather warmed up (A Blue tarp will absorb more heat)
Use logs or stakes (if your frame is on grass) to prevent the boards from falling over towards the outside and fill it with water! (the water/ice will prevent the boards from falling inward). It took about 3 hours to fill our rink up (about 1 1/2 to 2 inches of ice)
Wait for about 3 days of sub-freezing temperature(the colder, the better) and voila!
Building it was easy, maintaining the rink is another story.
Now, we just have to make our own home made zamboni!