That video is lit by a softbox or briese light (both popular in music videos) facing down about 30 or 40º likely five or ten feet from the subject. There may be a few other fill lights bounced off the walls or ceilings. She's wearing a lot of makeup.
Generally, good lighting is tough but this anyone can do with a little practice. You can rent softboxes for next to nothing from any grip shop or buy one for $200-$500, generally.
Vaseline diffusion is too strong and hard to control for most purposes. No one really uses it. Just buy a tiffen promist filter. A black promist or warm promist (1/2 or 1/4 strength, depending on your focal length) should work well but if you're shooting on video keep your aperture open and zoom in a bit, as super deep focus can put the little flecks in the filter into focus. There are a lot of other similar filters that will work, too (Schneider Classic Soft, which Spielberg uses a lot, actually--but for different reasons).
http://www.tiffen.com/promist.htm
Some prosumer video cameras offer a "soft skin" look but all it does is blur the red channel a bit. If you're really serious about this I think there's an After Effects filter (
http://www.borisfx.com/after_effects/bccae/new_filters.php ) that will do this even better. If you're proficient in After Effects--and it's not very hard and you can download the trial version if you like--you can create your own effect using some online tutorials. Then, when color correcting, add a lot of additional contrast.
The "glossy" look that you see in a lot of hip hop videos is mostly just low contrast soft, primarily frontal lighting, with a lot of contrast added in post.
If this is all Greek to you, just hire a professional. There are plenty of cheap cinematographers and After Effects artists out there, many of whom will even work for free. I know--I am one.