My first thoughts are:
1. Respect your audience (their time and their interest - good segmentation never hurts).
2. Bring your personality (flat videos are painful).
3. Have a distribution plan.
4. Add value (entertainment or understanding).
and as always: test, measure, test, measure, test, measure.
To give a bit more detail to this answer:
Content strategy... what assets do you have in place? Align the content to the funnel... put together a content production and publishing schedule. Decide how important YouTube is to your business from an awareness perspective. Without good content, the rest doesn't matter.
Distribution... how do you reach your audience with other pieces of content? Owned, Earned and Paid. Here is a quick checklist:
a, email campaigns/nurture programs
b, website/landing pages
c, YouTube
d, YouTube adwords/Virool/Zefr (pay per view)
e, Tubemogul/Sharethrough/Unruly (syndication platforms) (pay per view)
f, Social networks (Facebook, Twitter, LinkedIn)
g, Partner Sites
h, Blogs
i, Press releases
k, Sales assets
l, Email signatures
m, Other?
Repurpose your assets... put the videos in a PowerPoint on Slideshare. Transcribe the asset and publish a white paper or a landing page. Create a podcast.
Track... (impressions > views > attention span > known viewers > conversions > revenue).