It's a good decision to use color accents in our outfit if overall color is dark or neutral. Small color accents will help to make it look more vivid and stylish, will be working as interesting details and will make the outfit look balanced and complete.
Color accents can easily be done with bright color accessories. Bright scarve with a neutral or dark blouse, red shoes and bracelettes worn with black dress. The more contrast between accessory and clothing color, the more attention it draws to you. This is a very elegant and intelligent way of attracting attention as it does not look obvious unlike if you are totally dressed into bright colors. You even don't need bright clothing but bright color accents will be enough sufficient.
If you are not fond of wearing bright color clothing, you can add color accents to your outfits. They are a good way for you to make outfit more stylish.
Also it's a good way to get used to bright colors and adding them into your wardrobe gradually. Start with bright accessories, bags, belts, footwear, then consider wearing tops, t-shirts and shirts with bright prints and finally you will feel comfortable to implement more bold colors into your wardrobe.
Using color accents is also a good fashion decision for those whose budget is quite limited. In that case better to do a good investment into basic wardrobe items of a basic classic colours, complementing it with color accents. Not being able to afford a fancy color t-shirt, use your basic white color t-shirt and wear it with a bright accessory or a bag. Plain look immediately becomes very interesting and attractive.
Having a good collection of bright accessories, you can change them every day wearing with basic things from your wardrobe, and every day you will look different.
So it will also save you from the question how to compose your outfit and keep all colors in harmony. Clothing of basic colors can be worn with any bright colors thus any of your color accents can be used.
Make sure colors which you wear beside your face are from your color palette (if not sure, find in the post about fashion colors selection). If the color suits you well, it will be able to improve the outfit of a wrong color (not complimenting you). Remember this rule if for some reason you have to wear clothing which color is not your best (maybe uniform, or bridesmaid dress, or just a mistaken purchase during shopping).