You can create custom folder icons by using only the software that comes with your Mac. By taking the existing folder icon graphic and bringing it into Preview, you can tint the color and then add text, emoji or shapes to create a useful custom folder icon. Changing folder icons can be a little tricky and buggy, however. You can also use graphics apps to create more highly-customized icons and download icons online to use.
If you have a cluttered Desktop, you may want to occasionally hide the icons. You can do this with third-party apps or Terminal commands. You can also write a very simple shell script in Automator and save it as an app. Then you can toggle the Desktop on or off with a simple click in the Dock.