[FDCPR]

First I'd echo the tips that PrimeTime has offered you as following those tips will get you a long way.
Study and learn about the specific animal you are attempting to photograph, the more you know the better your opportunities. Learn how to move into and out of an area, if the ground conditions are noisy don't walk in a patterned way. Stop often, scan the area, move a few feet more until you arrive at your predetermined position. Dependent upon which animal you are trying to photograph certain senses may be more developed than others. Some have a highly developed sense of smell others don't, but most all species have eyes and ears that are much better than ours. Watch where you shadow is falling, sometimes your body may be hidden but since we love the golden light your long shadow may be exposed and giving you away. Avoid sudden and fast movements, slow motion is your friend. If the animal is present only move when they are looking away. Have your camera set up and ready, you may only get one or two shots before the shutter noise drives them away.
Parks and golf courses do offer a unique opportunity to photograph wildlife. They are accustomed to people and approaching them is easier. Practicing your skills in these type of environments will help you when you venture into wilder areas. One of the things I like to do in a park setting is watch how the animals react when people approach them. Most of the time they will retreat to a certain area, I then make my way into the retreat area and wait for their return. Use others to bring them to you, and when they leave slowly make your way out of the area.
Ethics are fairly simple, do nothing to endanger the animals around you, leave nothing but your foot steps. There is much more to this, but you will learn that as you read about the various species. Some birds don't want you near the nest, others don't seem to care as long as you don't touch.
Try to improve the area if possible, I photograph a lot on public land that are not parks but are not wilderness areas either. I always have a plastic bag along and pick up trash when I am finished shooting, even though this gets frustrating as it never seems to get better. Have fun, learn and respect the area and animals that live there.