Video Marketing... how to do it the right way?

I think you should include keywords (that you're targeting) into your Channel's name. Not necessarily a requirement but it helps with branding a niche. It might help get your videos rank higher in YouTube's search engine too (maybe).

For example, your video channel is about Movie Reviews

So the keywords you might want to target is "movie reviews", so hence your channel could be called "Top Movie Reviews by Andrew."

Not necessarily staying in 1 niche but it might help with getting rank on YouTube searches. Your channel is meaningless without organic traffic.

You also need referral traffic, which you can get from creating a Facebook Page. Get followers to your Facebook Page either by using Facebook's PPC advertisement (which is the fastest way but it cost money to advertise) and by joining related groups on Facebook and make a name out of yourself there. Then just post up links to your YouTube videos on your Facebook Page.

If you want to do multiple niches, perhaps you can create multiple channels. That's another option.

You can go either way; create 1 channel as an umbrella or create multiple channels for individual niches. Having 1 channel allows you to post up all your videos under 1 roof ... thus, helping to make your channel appear busy and active. Niche channels, on the other hand, helps with branding and possibly ranking.

It all depends on the type of product you want to promote. If it is a specific product, then a channel is good for that product but if you intend several products within a niche, a more generic niche term will be appropriate for the channel

For ranking purpose, it is good to include your main keyword in the channel name on which you are building your campaign. This is applicable if the channel is niche specific. On the other hand, the channel name can be a general niche term if you intend to create videos on several products within the same niche.

Furthermore, to aid the ranking of your videos, each video file should be named with the targeted keyword and the keyword also should be included in the title. Some school of thought believes that ranking is better enhanced when the keyword is repeated twice in the title and if you want to that, let the keywords flow naturally.