1. Choose the right breed. Some breeds are much better layers than others. If eggs are a priority for you, you'll need to select a breed that lays very well( 6 - 7 eggs a week). The easiest way to research this is to check a breed chart, like this one. Likewise, don't choose bantam hens. While they are cute and small, so are their eggs. That means you'll use twice as many of their eggs when cooking. They make nice pets, but aren't good egg producers.
2. Get the right feed. Chicks need chick feed. Pullets need starter feed. But once hens are of laying age, they need a quality layer feed. Make sure your hens have access to both feed and water 24/7.
3. Avoid supplemental food. All chickens need regular access to grit and oyster shell or ground eggs. But feeding them lots of supplemental food - like table scraps - actually reduces their egg production. I do give our hens food scraps, but I can always tell when I've given them too much; suddenly I go from one egg a day from each hen, to hens who take days off from laying. Incidentally, this also applies to "chicken treats" such as mealy worms and corn/scratch.
4. Avoid stress. Hens who are stressed don't lay well. Stress can include a flock that's too large, being in a run that's too small, moving, etc.
5. Consider winter. In the winter, when there's less light during the day, all hens will slow down in their egg laying. If you want to encourage better laying, you can add a light to the hen house. You can also choose a breed that tends to lay better in the winter, such as Australorps.
6. Keep 'em young. Sad but true; young hens lay considerably better than older ones. After the 3 year mark, few hens will continue laying an egg a day.