Here's what I have done to get videos hundreds of thousands of views, and on the youtube front page many times.
First off it has to be something good. If you want it to reach a real audience, it has to be really really good. Don't even try promoting it unless it will really have in impact.
Show it to a bunch of friends and watch their response. Don't listen to what they say about it, just watch their expression. If they love it you will be able to tell, if you even for a second they looks like they are not interested or are not completely engaged, then keep on working on the video until you totally get someone into it. Make sure you can get a few people totally loving it, don't lie to yourself, make sure they really love it.
One thing you can look for is for them asking to share it(don't let them just yet) but keep on working on the video until it's ready.
Before you officially release it, make sure you fully optimize it (the resources to do that are explained on bhw, so I won't go into it at the moment, but in short, at least make sure you have the right tags, geo tag it, and fill in everything properly, you'll be in good shape.)
Once you have, share it on reddit, digg stumbleupon and other social bookmarking sites.
Also use microworkers, mturk to do the same, get some diverse likes, and comments, also use twitter(I use tweet attacks) to hit up some folks on twitter.
once your video hits around 250 views, buy views, or use vagex or other things, but I recommend buying like 30,000 from there you'll show up in a bunch of related searches. From there you will have surpased the hump of all the other competing videos, in the end though if your video is awsome it will do well. If not it might do ok but it might not convert. Do amazing work and make it impossible for them not to share it(I'm not suggesting clickjacking, while I'm not opposed to it either
) But a great video you shouldn't have to clickjack anything, rule #1 do amazing work.
People will want to watch it.
I hope that helps.
