The best way to help animals is to support others who work directly with them, and to support agencies and organizations that help them, too.
Generally, the large, national organizations provide information and materials that benefit as many people as possible, such as brochures, programs and sometimes outreach activities. However, if you want to be sure your donations go directly to feeding or treating animals in need, locate a rescue shelter and donate to them. Most are non-profit groups and your donation will be deductible, if that is important to you.
It's also extremely useful and appreciated if you contact a shelter near you and ASK them exactly what they need, then provide it. Here at HiPAWS, we were lucky to have some generous people in our area who brought bags of pet food, cleaning supplies, old blankets and towels, bowls and trays, old litter boxes, cages, carriers, and even some used carpeting.
If you would like to help the animals here at the sanctuary, any donations go directly to their care, primarily for food, litter and veterinary care. Occasionally, we need to buy new litter scoops or collars, and supportive supplies like soap, scrubbees, brushes, paper towels, etc. Everything donated is used for these expenses only. Administrative costs come out of my own pocket, as do the primary expenses if donations aren't enough each month.
Here are some links to more websites that can help you decide how you would like to help: