I will assume that you have your own domain name, and we'll work from there.
The first thing I would do is sign up for a ping.fm account. Add all your services. Complete your profiles for all the services that are included. If your site has an RSS feed, make sure you add it so that every time you update your site you'll update your status on all your sites.
Write articles. Not really hard to do. With a 400 word article you write 3 tips, fill in each tip with 3 - 4 sentences, write a conclusion, and a resource box. Make sure you use relevant keywords to your site.
Best article directories are here. Personally, with the way things have changed, I'd write a different article for each one and then submit a different article to each one (You'll find tons of spinners here so spin your articles. Just make sure they read well, i.e. quality content.)
List Of Top 50 Article Directories By Traffic, PageRank
If you have a blog, of course, you want to guest blog. You can use a site like myblogguest.com or blogsynergy.com to help you find guest blogging opportunities.
Forums are great places to market, even now. Create a good profile, add a sig if they let you, and get involved. Look for forums that are popular, have lots of members and lots of traffic.
Free classifieds. Give something away. Build a list. Some good sites are: ******list.org, olx.com, oodle.com. There are others. Use Alexa to tell you the top sites for this.
Social marketing: Facebook, Myspace, LinkedIn. One thing I would recommend here is to look for social networking sites in your niche if they exist. You will actually have good or better luck marketing on these sites than if you market on the general sites.
The most important thing to do here is to learn one technique at a time. Use it. When you get it, add a new one. Marketing is the law of averages, and the more you market, the more you can test and find out what is working for you.
This plan I just gave you has built in backlink building. Also, if you want even more backlinks, the tool I use (I have no idea who owns this) is Comment Kahuna. I like this software because it will give you do follow links for blogs, and you can look for sites that use CommentLuv too. This will allow you to display the title and a short snippet for your latest post. It's absolutely free, but it does require you to sign up for the list.
Free Link Building Software | Comment Kahuna
Questions? I've written books on this, so if this seems a little siimplistic, I'm trying to condense a lot of information into a forum post and make it as easy as possible! LOL
Good luck with your site.