doh, i just posted a pile of suggestions in another thread
here. i'll try to summarise again here. these are just some basic tips, if you google 'seo youtube' you'll find more.
as others have said, have good content! it's the most important thing by far.
set up your Youtube channel well. a cool little one to two minute intro vid. put a good header image on the channel home page.
type some good text into the channel description, and get your keywords in there including your channel name. then try to work in keywords into your description.
every time you post a video, get those keywords into your video title. also put lots of text (at least 200 words) in the video description.
youtube will rank your video higher if you get lots of comments, and also if you answer the comments. so invite comments from viewers on various topics.
at the end of your vid, put a link to previous videos you think the viewer might find interesting. or invite them to subscribe, like or comment.
as you get quite a few videos together, see if you can classify them into playlists then link to these at the end of your videos too.
post your vids to various forums. i would suggest not going overboard with this as no one likes a spammer.
create as many social media platforms as you can manage such as the forums, facebook, twitter, a website etc and create links between these and your vids.
develop a consistent style and image that will be easily seen as yours. maybe make a simple logo for the start of each vid. Try to have your intro and endings done in a consistent way.
upload a good preview or thumbnail image for each video that also has your name or logo in the corner.