Monitor settings can mean the difference between seeing the contrast of color or borders and not. Many times your first instinct on a peculiarity can be correct. As you're scanning a page, don't be afraid to follow your gut and go back to the areas that catch your eyes. They do this by displaying a set of items/objects that look almost normal. Hidden object games often like to hide things in plain sight. It's often harder to rely on just the color or just the shape for finding objects. Think of it like looking for the octagonal shape of a stop sign versus looking for the red color. Looking for particular shapes is helpful when puzzles don't use colors as a distinguishing attribute. This can get tricky when game designers include sets of colors that are similar enough to get your attention but not to be what you're looking for. If you know the color of the object you're looking for you can focus just on the differentiation of colors and not necessarily the shape as well.
The contrast between colors/pixels is critical in finding hidden objects. Here are some basic tips on how to play hidden object games: First, there's no 'wrong way' to play - if you're having fun, strategize however you wish! There are, however, a few strategies and things to literally and figuratively look out for.