Numbers: Your address just needs to be the numbers to your address, not the street name.
Colors: Ensure the address numbers are of a contrasting color to their background. Black letters and dark paint don't stand out very well. Gold metal letters can be hard to see on light to medium colored back grounds.
Size of the numbers: A minimum size should be 4 inch letters with 1/2 inch brush stroke. The further away from the street your home is located, the larger the numbers should be on your home so they can be easily seen from the street.
Location: Should be visible from the street at all times, not behind brush, fences or large vehicles. If any of those are the way. Locate the address a sign post or mailbox instead of the side of the home.
Lighting: A good idea if you live in a dark neighborhood would be to put the address where light can hit it at night or add a light to the numbers.
Long or split driveway: With a long driveway, the address numbers should be at the street so emergency responders can find your driveway and then your home. If you have a shared driveway, you may put both addresses at the end and then one for each home where the driveway splits.