Wear sunglasses and a baseball cap to disguise your face and hair. If the target knows you, he or she may still recognize you by body shape, coloring or other features and traits - even if you are fully disguised. If possible, park in front of a store, bar, or service station. Slide over to the passenger side or slump down in the back seat. Pretend to be waiting for someone while reading a road map or newspaper.
Surveillance takes time, so relax and learn to be patient.
You may be sitting in one spot for a long while. Minimize eating and drinking to alleviate the need to break surveillance to locate a bathroom. When I go on surveillance I take a change of clothes - sometimes a couple changes of clothes. If I anticipate my subject may be going to the beach, I bring along a swim suit, towel, shorts, and shirt - anything I may need to fit into where the subject might be going. I change my appearance.