Hi Stephen,
Building a website can be a daunting task if it is your first one. Unfortunately, many people let this first step stop them because they have an idea that their website should be perfect. Too many times I've had people tell me that they will start promoting "when I get my website right."
The fact is, it doesn't have to be perfect. It doesn't even have to look good! Because as you learn and as you play with your site it will get better and better. Perfection doesn't come so much from knowledge as it does from practice.
So, here is my advice and tip. First, just get it out there. Spend a little time each day to improve it and learn more about what does what. There's no rush, as long as it's up there. You want the search engines to go ahead and find your site and work on indexing it for you so people can find you easily.
As you get better at building your site it will be time to learn about SEO. You don't have to be a guru or mastermind at it, but learn the importance of keywords. Learn all about meta tags (and if you haven't found this in the sitebuilder yet, don't worry, you will). Learn about how to do keyword research and find keywords that suit you, your site and the people you wish to attract.
Most importantly, have fun! The site should reflect who YOU are. So just have fun with it. In time you will have a site you can be very proud of.
Hope this helped a little.
Vincent Parker