Do you that when you open volume control the default is large size, you can change it to small size by pressing Ctrl+S. Pressing again will change back to large size.
When you have multiple windows open, you can close many windows you want by pressing Ctrl and clicking windows at the taskbar, after that right click and close group.
If you want Notepad to automatically insert date and time for you, you can press F5. If you want Notepad to insert date and time every time you open the file, you can write .LOG at the first line and save.
Even though these tips aren't that useful in my daily usage, I'm quite surprise to find these tips and happy to share with you all.