I always have my camera with me. If there are people around, I pretend I am taking closeup pictures. Macro photography always necessitates getting into odd positions, as does hunting for a microcache.
Other people incorporate an orange vest and a clipboard as a way of looking official and therefore less prone to scrutiny. Someone who looks official will not merit a second glance in comparison to a single person just milling around, seemingly without purpose.
Binoculars and a bird book are good for a disguise - you can always pretend to be bird-watching. A bird-watcher will hang around the same location for a while, watching birds, while the muggles move away from the cache location.
Anything you can incorporate into your "outfit" so you do not become an object of either suspicion or curiousity is a good thing.