Here's how I make mine.

Get a pitcher of water, a soda bottle, a tack, a pair of scissors, a piece of gum, and the bowl part of a metal pipe (but if you're just using things from around the house, you will need to find something else for a bowl). Poke a few holes in the bottom of the bottle and submerge it in the pitcher of water. Ideally you want all the water to drain out of the bottle in about 15 seconds or so when you take it back out. If it goes too slow, make the holes bigger. If it goes too fast, start over with another bottle.

Now, poke a hole in the center of the soda cap with the tack. Then open up the scissors and put the end of one blade on the hole. Keep twisting the scissors around, making a circular hole until it is just big enough to push the bowl into. If you need to, seal the hole around the bowl with the gum.

To use it, submerge the bottle in the water. Then screw on the cap/bowl thing with your weed in it. Then lift the bottle out of the water while lighting it. The water will drain out the bottom of the bottle, sucking air in through your bowl. When the entire bottle is full of smoke, unscrew the cap and inhale it.