Here are the 10 methods I used for getting links to one of my directories:

1. Directory submission
If you don't have time to do it your self, you should hire some one to do this for you, as this is the best and the safest way to increase your back links.

2. Link Exchange With Other Webmasters

This is a slow process and not always reciprocal linking is a good idea, cause search engines place more importance on one-way links than two-way links. Still, it can bring you valorous links, if you have what to exchange with.

3. Build A Network Of Websites And Interlink Them

Building multiple websites is always a good idea, but be careful to host them on different ips, not on the same server, as the search engines will believe you are manipulating their results and will most penalize your sites.

4. Write articles like this one. You can see in the footer my bio-box, that has 3 links. as you see, I am not writing the article for nothing.

5. Build a reciprocal directory
If you build a niche directory related to your site, many people with similar sites to yours will want to submit a link to it, and, in return, you could ask for a link to your site.

6. Build a theme / template for used scripts

Like Wordpress, or phpld. Put in the footer of the theme, your link, as in "Designed by yourlink.com". If you can't do one, you could always buy it from people that can. The catch here is to advertise it well.

7. Post on forums that allow you tho have a signature

You won't get a great deal of of page rank, as most forums do not have a high page rank for their threads, but you will build up a good number of links, and as forums are generally very crowed by search engines, bots will follow the links to your site and and crawl your site on a regular basis.

8. Leave Comments On Blogs And Guest books

Don't abuse it and start spamming other people's blogs or guest books. Make comments to the subject, and make it look like you actually have something to contribute.

9. Write Good Testimonials

By writing and submitting testimonials to websites that you have previously purchased products or services from, you can get high-quality links to your site.

10. Buy Links

This can have a dramatic effect on your page rank and subsequently your search engine rankings if you can get links from PR6+ sites, however the only problem with this is that most links for sale are often for a set period of time, usually a month, and so you have to keep buying them to maintain your higher page rank and rankings.