As this method is so easy, I'll just give it to the community. There are three elements. First, be sure the title of your video matches your keyword. Second, be sure to add a good description with keyword and related terms. You can put a call to action here also. Third, get views and likes. Depending on the keyword difficulty you might need more or less. I've been ranking videos with a difficulty of about 1M - 2M competitors (Google) with a few hundred views and maybe 20-50 likes. Note that your view count on YT will stall at about 300 - this is normal. Just keep getting views - YT is still counting them.
Where do you get the views. I prefer to use a social exchange site (AMF, YLH, etc.) to get the first batch of views. After that if you need a lot more you can get them on Fiverr.
If you're shooting for super competitive terms you'll probably also need to do backlinking to your video.