There are lots of things you can do to get more backlinks. It's been discussed here a lot so I'm sure a little searching on the forum will offer some good advice.
One thing which you've already done is to add a link to your signature here and I hope at any other forum where you post.
You can submit your site to directories. There are a lot (probably too many) online. One of the forums here is a
submit to my directory forum and to get accepted to most of them you'll just need to fill out a form. Not all directories are created equal though so search around. I'm sure there are some threads here with lists of directories so try searching for those too.
You can also find directories or other places to possibly get a link by searching in any search engine. Try things like:
"your keyword phrase" + directory
"your keyword phrase" + "add url"
"your keyword phrase" + "submit url"
"your keyword phrase" + "add site"
"your keyword phrase" + "submit site"
replacing 'your keyword phrase' for the phrase(s) you're targeting. There are also many other varieties of the searches above.
Another way is to try a search on your keywords and then look for who links to the sites that show up at the top of the results. You can find who's linkint to them by typing:
link:
www.domain.com
Google will only show a sample of the links and with Yahoo you need to include the http://
The results to the link search are pages linking to the top sites for the keyword and are possibly places you can get a link as well.
You can also write articles and include a bio with links back to your site. You then submit those articles to free article directories for others to download. If you do a search here for 'articles submission sites' (I think that's the search) praveen started a thread listing more article directories than you'll ever want to know about.
In the end having good content is the best way to get links. Offer things on your site that people want to link to. Quality content is one way, but you might also be able to offer free online tools for your industry.
Those aren't the only ways, but should help you get started.