Offsite Optimization nothing but link building your site in all possible way like directories, blog, article.submissions etc. Do link your site with quality backlinks.Choose the best site for linking, Good PR site with less external linking.Choose the only relevant category for submissions.
Publish your website publically or socially is called social bookmarking, it is very helpful in providing back links and getting higher traffic for the website.
Getting tons of back links won't work on SERP. Important factor is relevancy. concentrate on theme related back links[In case of reciprocal linking it should be theme related and we need to consider age, PR, no of O/B links], then go for other sites for one way links.
Press release is for publishing your articles about your products & services. Submitting press release gives a high pr backlinks.