Go to the actual video that you want to download.
In between “www.” and “youtube” (in the address bar) add the letters “ss.” Your URL should now look similar to this:
Press the enter key and you will be directed to SaveFrom.net, a website that will allow you to download the video. Note: By default only the MP4 video format is displayed, but you can click the “more” link to show more formats like FLV and 3GP (for mobile devices).
Click on the format and quality (ie. 360p, 480p, 720p) that you want to download. The video should begin to download, unless you have your browser set to “Ask where to save each file before downloading,” in which case you’ll need to choose a place to save it first.
Now, you can enjoy the video at your leisure.