I'm fairly new to the SEO biz so you can take my advice with that in mind. For about two months I have been trying out a multitude of techniques to see how it affects my rank in google, here's what I found out.
Give and you will get
find people who are looking for your service/product in forums and give them some advice (good quality advice) if your service or product is any good then this should not be a problem. Also, leave comments on blog posts that pertain to your service or product. Try to leave a link or at least leave a link back to your site in your name, but don't force it other wise you could get kicked out for spam or get your post removed, which could suck if you spent a lot of time on it.
Do key word research or pay someone to do this (can be time consuming). Pick one and stick with it even if it looks like it's not working. I'm trying to rank for cheap college textbooks
this key word phrase is very competitive and I didn't see any results for a month and was about to try another, then on about day 30 it started to show up. You can use some software like SEO PowerSuite, they have a free version, so you can see how you're ranking.
Numbers don't lie
Check your rank and check your analytics, but don't get caught up with it. Whether you admit it or not most of the people who visit your site will be you! Well at the beginning at least. So take some time off from your site, either spend 5 minutes a day on numbers or an hour once a week. But, your time would be better spent networking, helping others, or joining new sites.
Learn the basics
When you leave a link, some sites use html and some use BB code. A html link would look like this <a herf=".... while BB code (what this site uses) uses [ instead of < make sure you're using the right code. Always put http:// before your web address and always link to the same address. One website has about four ways to get to it for example;
these may all seem the same but google sees them as four different sites with the same content. stick with one www.wikipedia.org/
You are who you hang out with
Don't just post on any site or forum, spend some time on the site make sure there is no sign of any spam. This is very important, in just over a month I was nearly on page one of google for my key word phrase cheap college textbooks
but I made this mistake, I posted on a site that looked legit, I thought I was posting on a page with 3 other comments, when in fact I was posting on page 13 of about 100 other comments. Now my site is MIA! If you even google my sites exact name dirt cheap college textbooks
it won't show on the first page, but articles and PR will that I wrote on other sites. That's why it's good to give as these will rank high even if your site is not.
There are no quick fixes! You have to understand that google is smart, very smart if someone writes a post about a quick way to rank high in google chances are that you'll find it through a google search, which means it's already known by google and someone in google is saying anyone who does that quick fix is cheating jerk and should be punished.
Start writing PR, articles, how to's and post them on other peoples sites. Some good sites are squidoo.com, prlog.com, and tumblr.com.
From what I've seen google updates it's ranking daily and your site can move up or down that quickly. If your providing quality on your site and up date it regularly then your on your way. What I have given you here is an ice cube of the ice berg that is SEO.