Steps
Place lemon and orange peels in the garden - many cats hate the citrus smell.
Spray bitter apple juice or vinegar around the garden and yard to keep dogs away.
If you have an animal digging problem, try sprinking red chile powder around the areas the animal is digging. Most animals hate chili powder.
Use Hot Pepper Wax spray on the plants. It is a natural food wax and won't wash away during the rain. This will keep most animals (and a lot of insects) from eating your vegetables and doesn't harm the vegetables in any way - just wash them off after picking.
Dog urine keeps other animals away as well - dogs and cats are fearful of the dog living at the house. This can be purchased on the web and at some specialty pet stores.
Install a motion activated sprinkler which shoots a jet of water at anything entering the yard. Keeps out kids too until the first hot day comes...
Tips and Tactics
You can purchase professional animal repellent at the pet store - over time, this gets expensive.
Cats hate walking on aluminum foil, try laying some around the garden to see if it keeps the cats away.
Cat's hate walking on chicken wire, lay it around the garden.
