Before you choose the faucet that's right for your kitchen or bathroom, you'll need to establish how high you want it to be and how far you want the spout to reach over your sink. Buying a faucet without measuring up can result in your plumber fitting a tap that's not suitable for your sink or having to return your faucet to exchange it for a new one.
Determine the ideal height for your faucet. This will depend on the height of the sink and how tall you are but will be primarily dictated by personal taste. You should make sure everybody in your family, including any children, are able to reach the faucet's tap controls, especially if these will be positioned at the top of the faucet as opposed to the sink's edge.
Measure the distance from the faucet piping line -- where the faucet will be installed -- to the sides of the sink in a straight line. You need to make sure that any faucet you buy doesn't reach over any of the sides of the sink but that the spout easily clears the edge of the sink where the faucet will be plumbed in. Make a note of the measurements you take.
Bring in your measurements to a plumbing supply or home improvement center to find a model you like in the dimensions you require.