I think your design plays a big part, closely followed by the name. What makes a great design? Simple, make something that catches the eyes of your visitors, grabs their attention, and makes them want to stay. For example: My site http://www.movieguys.org used to have a plain text header that read movieguys.org . Since I have updated the header to include the logo, and made the text a little fancier I have increased the unique visitor time on site a whopping 90%
Check out some CSS design galleries (cssheaven.com, cssdrive.com, csselite.com, etc). Just google "CSS gallery."
Another thing that really draws my attention is when someone is very knowledgeable or has a certain expertise on a topic I am interested in. A way to get noticed is by proving to others that you are that guy/girl. Shoemoney and Zac Johnson are both great examples. Just by posting their whopping checks that they earned from working online they have proven that they really know what they are talking about. Thus more people are willing to listen/subscribe/visit the site. That's a great way to get popular/noticed really fast.
Unique great design for sure and I believe an eye-catching short brandable domain name too (preferably .com).
If you really want your website to stand out from the crowd then take a look at the following website. www.takeactionwebvideo.com They offer live website actors that will appear on your website and captivate your visitors. I have had great success with this method of making your site stand out.