Good Wallpapers are mostly monochromatic, becoming a non-intrusive background when windows are on top. But they can be any style otherwise (photo, abstract, drawing, etc.)
(Ascent is a good example that was included with Windows.)
Two types of desktops
Desktop is a blank canvas for windows. Files are accessed from file explorer instead of the desktop.
Instead of program shortcuts, the desktop is a place for files and folders that you're currently working on. Probably improved by using Stardock Fences. Requires some effort to prevent the desktop from becoming unusably messy. (This would always happen to me, I keep files off the desktop now.)
The Windows 7 taskbar was a mistake
By default separate windows are combined into single icons. Because of this it often takes two clicks to switch between running tasks, previously it only took one. The benefit of this is to have your screen filled with quick launch icons that aren't being clicked on 99% of the time. This is redundant. It's easy to start a program on accident while attempting the incredible common task of switching between the programs you were already using. Using the Win10 task view as an alternative still takes an extra click or keyboard shortcut, and it's disorienting because you're not sure where each window will appear on the screen.
Everybody complains about the lack of tabs in the file explorer, but the file explorer was already tab-like before the taskbar windows were combined. With an uncombined taskbar it's easy to click on the wide buttons, so it can take up less space on your screen.