1.  Add #t=XXmYYs ( XX is minutes and YY is seconds) at the end of URL if you want this video playing at XX minutes and YY seconds.
Example: youtube.com/watch?v=_OBlgSz8sSM#t=00m30s begin to watch this video at 00 minutes and 30 seconds.

2. Add &start=25 at the end of URL if you want this video playing at first 25 seconds.

3. If you do not want the search box show at the end of the clip, you can hide it by add &showsearch=0 at the end of the URL.

4. Normally, you must click “Play” to watch the video. Now, you can add &autoplay=1 at the end of URL to auto-play this video. If you want this video auto-replay, add &loop=1.

5. When user post videos, YouTube will refer some videos and sometimes, it makes us uncomfortable. Add &rel=0 to URL to hide it.

6. We have many choices to download videos from YouTube, but the easy way this change “youtube” to “kickyoutube” in the link. After that, you will go through kickyoutube.com and download this video.