So I want to improve the SEO rankings for a site of mine, but this time it is different from my past sites because it is in a VERY out there niche. It is for selling machinery manuals and parts lists, so it is hard to find partner websites. I have submitted to popular directories, but other than that I do not know what to do. Is there anything you guys can suggest? The site is http://www(dot)industrialmanuals(dot)com Appreciate the help
Try to find blogs that are related to the niche. You may search on Google and others. Make comments there. You can get paid reviews from them. Also you can submit on social networking sites, classified ads etc.
good tips. @ OP, you can search the BST section and will find lot of members selling links/blog posts, etc. try to find some in your niche and get some backlinks. if you want to build backlinks for free, then commenting on relevant blogs, SB submissions are couple of good ways.
After looking at your website it appears that some good old basic SEO might help. It would also help if you had a way of adding some fresh content on your website. Of course quality relevant links would also be beneficial as well.