I make sure that the title tells what the hub is about. At the beginning, I found I wasn't using the words (book review) anywhere in the hub, and thought that was something I needed to do. I don't really try to add keywords too much in the hub, but if there is more than one word (patchwork vs quilting) or spelling (lawnmower vs. lawn mower) that I try to use them both. I do add captions to photos that refer to the keywords in the title. I add misspellings in the tags. (geneology)
I figure that the relevant keywords will show up naturally on the site as I write my hub, and don't worry about density. I always add a summary.
I title my paragraphs with heading tags. I don't really use the Adwords tool very much. I add links to other sites only if it would help my readers. I do include links to my other related hubs just to try to keep my readers on my site if I can.
When I finish, I usually add a link to my hub on Facebook or Google +, or both. I rarely add older hubs to these sites. I do have an RSS feed that shows up on my blog so the latest hubs are listed there at all times. I haven't been very active with blogging since I wrote here.