How do to make a bottle rocket?

You can strt by first constructing the rocket body. Using a sheet of computer paper build the body of the rocket and fold it half lengthwise. Cut the paper in half as folded and then take one half and fold it further in half, do it cross wise.

Now you should have one half of the original sheet along with two quarters of it. Fold one of the quarters to half and fold in half one more time but diagnally. Cut along the creases which is created from the folding in order to create four triangles which can be used for the fins. Now you have to take the other quarter and draw a circle on it. Cut it out and mark its center. Sketch two lines which should form a right angle from that point. Cut out the portion marked by those lines and make a cone out of it. Next, take the half of the paper and tape it around the canister. You need to place the canister along one of the edge of the paper and make sure that the opening of the canister should point outside of the cylinder formed by the paper. Now, tape the fins on the part of the cylinder paper which is near to the canister while tape the cone on the other end.

Hope this helps.