I saw my hummingbird for the first time this season a couple of hours ago. If you have a hummingbird, you can make them some drank (aka nectar) like this:
mix 1 part (by volume) sugar with 4 parts water. DO NOT add food coloring, it's bad for the birds.
You need to change the water so that bacteria don't grow in there. Here's the schedule of how often it needs to change, depending on the daily high temperature:
Temp (°F) # days
If stuff starts growing in your feeder, you can use a mild bleach solution to soak it in and kill the stuff. Rinse it out afterward. Don't worry about hurting the hummingbird because the sugar will neutralize the bleach.