I'd add to your list:
- Keeping a presence on Goodreads, pitching your titles to relevant book clubs etc.
- If you're posting an image on Facebook, why not post to GooglePlus, Pinterest, etc. too!
- Engage other authors. The relationships you build are invaluable in this lonely journey.
- If you're looking to give away a large number of books to reviewers, try LibraryThing. (I offered 100 ecopies of my book for review and I think about half of those people actually reviewed it.)
- Make a $5 book trailer with Fiverr, establish a Youtube presence/channel.
Other tools that I've found helpful:
Use Hootsuite to manage, schedule your posts on Twitter, Facebook, GooglePlus, etc.
Use Triberr to connect with other bloggers, reach a larger audience and help other authors/writers promote their work.
Create a Google Alert to crawl the web for discussion threads in your genre, or mentions of your book.
Set up a keyword search of your name/book with Hootsuite so you can thank people for Twitter mentions or join the chat.
Use Rafflecopter to manage your contests and giveaways.
Mediagig on Fiverr made my book trailer in less than a week. I highly recommend him. (I did a few add ons and it cost me $15.)