Keep in mind that hummingbird feeders are mainly for the benefit of humans. After visiting the feeder, the hummingbirds go on about their usual activities - slurping nectar and eating thousands of gnats, small spiders, aphids, etc.
The following information was provided by Helen Bishop. Helen and her associate, Jean Roper, are quintessential hummingbird rehabilitators. They only accept hummingbirds (several hundred annually), because this specialized skill requires a tremendous amount of time and labor.
Purchase a feeder that has no hidden areas. Be sure all inside surfaces can be reached and cleaned with a bottle brush.
Boil the water for several minutes before measuring in order to avoid volume loss due to evaporation. You want to end up with a one to four ratio so that the mixture will closely match the sucrose content of flowers which attract hummingbirds. Cool to room temperature, then fill the feeder.
Maintain feeder cleanliness. Wash the feeder with very hot water every 2 or 3 days. Use a bottle brush to scrub all surfaces. If the feeder solution becomes cloudy, empty and clean the feeder immediately. Sanitize the feeder at least once every month with bleach. Soak the feeder for one hour in a bleach solution which contains 1/4 cup bleach per gallon of water. Then air dry the feeder completely before refilling. The hummingbirds prefer that you perform this sanitizing procedure after dark, and have the feeder refilled and ready to go before the crack of dawn. Don't use soap to clean the feeder. It seems to take forever to rinse all the bubbles out. Remember, if the feeder isn't clean enough for you to drink from, then its not fit for hummingbirds either! Please note: By not following these instructions, you could be responsible for giving hummingbirds a serious and deadly fungal infection. This infection attacks the tongue, making the hummingbirds unable to eat. Ultimately, they die a slow and painful death from starvation. Please do it right or don't do it at all.
If you don't have the time to be a serious hummingbird feeder owner, perhaps you would rather plant a hummingbird flower garden instead. That would probably be a better choice anyway. Your local nursery will be glad to help you select the flowering plants (potted or seed packets), which hummingbirds prefer. Also, you can put out old apples, bananas, etc. in a small container. This will attract small flying insects. The aerobatics a hummingbird performs while snapping up these small insects is very enjoyable and sometimes even humorous. Always make sure that the places in your yard that attract hummingbirds are free of hiding places for cats. With practice, cats can become adept at picking off hummingbirds. Don't spray any insecticide on the flower garden either. Hummingbirds don't tolerate bug spray very well. Moreover, the hummingbirds must have the spiders, both for food, and nesting material. Notice the hummingbird nest pictured above. It's made mostly of spider webs. A hummingbird nest is about one inch in diameter, but will expand as the babies grow. This expandable nest keeps the baby hummingbirds warm and comfortable.