In no specific order, feel free to add if you'd like.
1.) Low prices doesn't necessarily lead to clients.
2.) People are willing to spend more money then they know. (Yes.. THEY)
3.) If it takes you more then 5 minutes to do, you should be getting paid for it
4.) Be prepared to mess up; time and time again. (before getting it right)
5.) Most people don't really care about free services. They expect to pay, you should capitalize on that. "Free" services actually turn people off.
6.) Aside from the landing page clients will visit probably 1 or 2 other pages. Make it count!
7.) PPC is the best way of discovering what keyword work and don't. Even if you use it for a few days or a week. It's great.
8.) Anyone who promises you overnight SEO results ranking is usually lying.
9.) Think as a customer.. not as a tech when pricing your services.
10.) Facebook is an extremely powerful tool for getting on the 1st page.
11.) Google Analytics is your best friend. Use it wisely.
12.) Webmaster tools is your best friend. Use it wisely. (Especially when you need your site indexed)
13.) You can now link your website as an annotation in Youtube videos.
http://www.youtube.com/watch?v=RrJ0_-LUQ8o
14.) Treat every job like your life defends on it's success. They sometimes lead to much bigger jobs.
15.) Don't be afraid to take something to a competitor if your not equipped to fix it. (i.e. televisions, speakers, etc) Clients don't care how and where you did it.
16.) Be honest.
17.) Keep it simple, short, and to the point. Most don't care how smart you think you are. Unless they ask, keep the jargon to yourself.
There's alot more, but I think I've covered the most important ones.
Just try to keep it in perspective, eh?
