Here are some fast and easy keyboard shortcuts to save time in navigating YouTube videos:

- To pause or play a video, press the space bar.

- Press m to mute/unmute the video.

- Move 10 seconds forwards by pressing L, and 10 seconds back by pressing j.

- Press f for full screen and Esc to go back to normal screen size.

- Use the < and > keys (with shift) to slow down or speed up the payback rate.

- Press 0 (zero) to go to the beginning of the video or End to go to the end of the video.