As an SEO expert, I think it is our responsibility to make people/clients aware of some of the issues to deal with off-page SEO. Most things you can be aware of and some may be hidden treasures for you.
(1) Community building: Also referred to as online reputation management, this is the first step you take. Sign up with popular social networking websites like Facebook, MySpace, Orkut, LinkedIn, and create a profile for your website. Connect with friends, share with them, and promote your company. This will help you increase your online reputation. These are popularly called Web 2.0.
(2) Blogging: This is one of the most powerful strategies for promoting your website online. Write a blog with unique content. To make it clear to your readers but don’t forget to promote your blog in blog search engines and blog directories you can also post comments on other websites. If you don't like the written content, hire someone!
(3) Forums: If possible, create an online forum/discussion board hosted on your site. Invite your friends to start a new discussion. Post answers/threads in other related forums. Your signatures can provide you with valuable links.
(4) Submission to search engines: This is an important step. Submit your website to popular search engines. To name a few: Google, Bing, Yahoo, Alexa, Althub. Search engines can submit as much as you want.
(5) Submitting directories: Nowadays people think that submitting directories is useless. But in my view it is still alive. All you need to do is be careful about which directory you are going to submit your website to and in which section it will be submitted. Try submitting your site to DMOZ, Zoominfo, a mission. Never go for a given list.
()) Social bookmarking: It can be a powerful tool but don't abuse them. People post content on social bookmarking sites without knowing the right way to take advantage of them. Manage tags correctly. A few follow-up links can give your SERPs a big boost.
()) Link Exchange: Try exchanging links with industry-related websites. This can give your SERPs a big boost but be wary of black hat strategies when exchanging links with other sites.
(8) Link Biting: Many people do not understand link biting and consider it a black hat. This gives proper credit to the author / original source from which you copied the content. If you follow this, there is a chance that others may follow the same practice.
(9) Photo Sharing: When done correctly it can bring handsome traffic to your website. Share product images and make them public. Invite your friends to see/comment on them.
(10) Video Promotion: In addition to sharing photos, you can share or publish expert opinions on major video publishing sites such as your product videos, YouTube, Metacafe, Dailymotion, etc.
(11) Business Review: Write a business review and ask your friends/clients to do it. Some of the big sites are Shubhong, RetitL, StyleFeeder.
(12) Yellow Pages and Local Listings: If the nature of your business is service-oriented, try to dominate your local market. Sites like Google Maps, Yahoo Maps, Yellow Pages, Hotfrog, Super Images.
(13) Submitting articles: This is one of the oldest ways to gain backlinks. Submit your website to good article directories like ezine, go articles, bazal etc.
(14) Press Release: Submit to your PR sites like OpenPR, PR Leap, 1888 Press Release.
(15) Classified Submissions: Post your products/services on classified sites like Craigslist, MySpace, Vivastreet.
(16) Social Shopping Network: If you have an e-commerce site, this can be a good strategy and help you get free branding. Submit your product feed to MSN Online Shopping, Google Product Search, and Yahoo Online Shopping.
(17) Answer: Try to help people; People will help you in return. Answer the questions people ask. Sometimes you can put a link to your site in the resource box. Some great sites are Yahoo Answers, Answer Bags, Tea-Tea, etc. But don't spam!
(18) Document Sharing: Share your business documents, slide by slide, Google Docs. It helps to create a brand.
(19) CSS, W3C Directory Submission: If you provide website design or related services, submit your websites to the W3C and CSS Directory in addition to the RSS site.
(20) Gadget / Widget Development: Develop some interactive gadgets for your site. Publish these to your website/blog and another social networking website. Make your friends and the world aware of your brand.