Wild bird food is the best way to attract birds to your yard.  The type of food you put out will influence the birds who come to visit.  Most feeder birds like black-oil sunflower seed. Don’t confuse this with the sunflower seeds humans eat!
Nyjer seed is preferred by finches. And peanuts are appreciated by most.
Suet cakes are a high energy food and are preferred by insect-eating birds such as nuthatches and woodpeckers. In hot weather suet will spoil quickly, so keep it fresh.
Nectar. which is basically sugar water, is for hummingbirds and orioles.  These birds are attracted to red, so you will often see red portals on feeders.

Don't miss our outdoor edible orniments for birds!!   A new product we've found can either be a feeder or food!  These are lovely ornaments that hang from outdoor trees and are, in fact, bird food. Birds love them and flock to them, so you will get many hours of joy watching them.

The Cornell Lab of Ornithology (link 3d on the links page) has much more detailed information on food, plus the following warning:

“IMPORTANT: Change nectar every three to five days to prevent mold and deadly fermentation. NEVER use honey or artificial sweeteners. Honey readily grows mold that can be harmful to hummingbirds. Do not put any kind of oil around feeding portals to deter bees; you might contaminate the nectar. If bees or wasps become a problem, try moving the feeder.”