Found press releases don't help that much. More forums,blogs,article postings.

the most effective way of creating links is forum posting. Yes the same you are doing but should be in legal manner. Other task you can performs as well such as business listing, RSS , social media activities etc.

Meta Data Modification
Content optimization
URL Structure Optimization
Redirects and Specified urls
Google Webmaster Tools
Google Analytics

Have you tried social media optimization? Its one sure way to increase your loyal customers and to keep up with your website.

Firstly start with On-Page then go with Off-Page optimization.

Do social bookmarking, forum posting, blog posting and commenting on high PR sites. Also use social media site for improving your site visibility in search results.

Best SEO methods for link building are directory submission, article submission, forum posting, profile submission, social bookmarking and blog commenting.

1 Forums Post
2 Guest Blogging
3 Blog Comments
4 Article Sub
5 Classified
6 Yahoo Ans
7 Social Networking (Google Plus, Facebook, twitter)
8 Directory Sub
all these are very important method of SEO

Link building is the best seo method.