The most wearable scarves you own are those which coordinate with your already exisiting wardrobe. Chances are you already have a color theme—a set of hues that you wear well and which convey the image you wish to project.
If you have a scarf that is not in your usual color either becaue you were enamoured by the hue or because someone else was enamoured with you and gifted it—it will likely coordinate with something neutral in your closet. Always try your scarf with black, white and neutrals. Bear in mind that these have warm and cool variants—so if white doesn't work, ivory might. If cool grey (bluish) doesn't work, try warm grey (brownish).
When exploring coordinating options, make sure you do so in both natural and artificial light.
If a scarf's color seems right but somehow it doesn't work with the outfit, try wearing it differently. The amount of visible color is significantly reduced by folding. A loosely draped triangle has a totally different look than a neatly folded rectangle, tied smartly at the neck. When checking scarf compatibility with an outfit, look at the scarf I the context of the neckline. For instance, adding a shawl collar jacet to a boatneck sweater totally changes the line.
Getting the big picture is always helpful when putting together an outfit. Try on the whole ensemble and view it in a mirror from a distance. Squint to blur edges and allow your eye to mix color. Look away and focus mentally and visually on something for a little bit so when you look you will have fresh eyes.
Ideally, your accessories should include at least a few scarves. A well rounded selection of scarves includes warm, cool, classic and neutral palettes for maximum choice. These colors can be soft, bold, or dark. Color combinations which combine these categories are often appealing but more difficult to coordinate with most wardrobes.