Using a wider, shallower pot rather than a tall, narrow one is the quickest way to boil water. Remember that the larger the surface area, the greater the heat from your heat source.
If boiling a large amount of water, you should use a large pot or pan with a small surface area. This allows you to boil it faster and more efficiently.
Another method for quickly heating H₂O is to fill your pot with hot tap water rather than cold. It will give you a head start and get you to the boiling stage 1 to 2 minutes faster, depending on how much water is in your pot.
Finally, cover your pot or pan with a lid when boiling liquid. This will aid in the retention of heat and the prevention of evaporation, thus decreasing the amount of time you will need to spend in the kitchen.