I learned using Stefan's tutorial. You really don't need a video to learn clock. (Or any puzzle for that matter)
http://www.stefan-pochmann.info/spocc/speedsolving/clock/
General advice for getting faster:
1) The clock doesn't always need to face 12. You would just do everything as you normally would, except when you finish each respective face, you have to align it to a direction that isn't pointing up.
2) Practice pin patterns. Keeping your pin patterns relatively consistent will make you faster and ease the look ahead. If you follow tip one, then you should be able to get by solving any "lucky" case of a clock with only two pin patterns. I use the following pin pattern for my second side:
(ddUd or dddU), dUdd, Uddd, UdUd, UUUd, UUdU, UdUU, dUUU, UUUU
I'd like to get better with this pin pattern though, and stop doing dddU as the first move of the sequence above.
dddU, Uddd, dUdd, dUdU, UUdU, UUUd, dUUU, UdUU, UUUU
The reason for this is that you don't have to use your right index finger for two different wheels on the first two moves, unlike the first pin pattern starting with dddU.
3) Practice solves with two "lucky" cases on each side that are a different orientation. This will help you understand how you'll need to flip the puzzle and remember where 12 is so that you can take advantage of these lucky cases. That being said, I would practice doing the same pin pattern over and over regardless of lucky case at first just so you can get comfortable with the pin pattern, then try this.
EDIT: Also, Rubik's is well worth it. The knock-off clock is fine for beginning, but if you're going to get serious about clock just go get one on ebay.