After you add the keywords in the keyword area, also type them at the bottom of your description, AND VERY IMPORTANT put the most likely searched words in your title, if possible.
Then in order to show up higher in the search results you must search the term and click on your video, you don't need to watch the video just search it and click on it.
Continue to do this until your search results reflect what you want.
I know this first hand because for my film Surviving Death. I've decided to release it on youtube as a promo for a future series on the same subject. My key words are NDE, Near Death Experience, or the name Surviving Death.
At first it only showed up on the first page of results if I put Surviving Death Documentary. But now after repeatedly doing this process Surviving Death now showed up as the #2 item for someone (other than myself). The reason this is significant is because there is a Discovery Channel show by the same name and at first when the video was only a few days old it was on the 3rd page.
Good luck hope this helps anyone interested in adsense etc.