Be cautious about submitting your website if any of the following backlink methods occur (You may need to view source code to find some of them):
Don't submit to sites that aren't relevant to the focus of your site.
Avoid pages with links inside of frames (this will steal your traffic).
Don't submit to blog networks and limit blog rolls
Don't submit to article networks (they post your article to multiple sites).
Don't let anyone link to you from every page of their website (sitewide links unless they are nofollowed).
Free for All Links - they allow anyone to post a link unreviewed which results in unrelated and spammy links (banned by search engines and may also affect your site if you link to it).
Link farms - 100 or more unrelated links on a page (banned by search engines and also your site if you link to it).
Bad Neighborhoods - Poooorrrrnnnooo or gammmmbling or drug sites (banned by search engines and also your site if you link to it)
"I'll link to your website if you link to my other website over there" is called a Triangular Linking Scheme (can cause your website to be penalized or banned).
The site has a network of mirror sites with exact same web links (these sites may be banned and your link on their site will produce no benefit).
Avoid submitting to directories that don't review submissions and let anyone in.
Avoid submitting to directories that have several Google ads disguised to look like their own content above the other links as they are likely to be penalized.