When you walk on a street, have you ever thought that how those women be so beautiful and elegant. It's not because that their dress or outfit are beautiful but they can collocate well with their dresses, shoes and bags.
First in color collocation, it's true that more that three on your body will be a disaster except you go on the unusual way.
Sometimes, a sky blue earring can be a plus to your whole outfit.
Basically, the color of your bag should be the same with your shirt or pants if you wear usual clothes. on the contrary, the bag's color could be the a highlight of your dress.
When you can decide which color of the bag or shoes, pick a neutral one. That's a truth.