Answer 1

You mean the Hex Color method. There is no fastest method and you don't need to memorise it. You get familiar with very basic colors the more you work with CSS. You could use browser's developers tools to help to choose colors. I am on Linux and I have handy app called swatches. I just key in a basic hex color like red and I get all shades of red. So please don't memorise you will hurt yourself than good. Happy coding...