1. producing actual, physical books (to get word of mouth buzz going and give to book bloggers - plus it shows that you have confidence in your work.)
I personally feel like this is a waste. That is unless you plan to go to small local book stores in person and try to get your books on the shelf. (I am considering trying this) I have generated at most 2 non-family/friend sales because of my print books. To compare, book one of my series has generated over 15,000 "sales" as a free ebook. That has created a demand which has lead to book 2 and 3 selling at $2.99 a copy, as ebooks. Not best seller's, but enough that I can now afford a professional editor and pay my cover artist. I also bought my wife an iPhone with one months check.
Keep in mind, I did not dream up with this plan. I merely figured out it our by watching what other people did that worked. Sure it won't (and hasn't) work for everyone, but it does work for me. Each will have to find what works for them and work it.
That being said, I will continue to produce print books ONLY because my mother wants one for her shelf.
Also I think we may need to define "success." Is success being the next Rowling or King? Or is it having a following that pays you to do what you love to do, which in my case is tell stories? My current sales show I have accomplished that much. People would not be buying book three if I had not. So am I a success? Guess that is in the eye of the beholder.
Am I looking for ways to increase my readership, and do better marketing? Of course, which is evident in my hiring of an editor for book 3. I love to read others ideas (like this thread) to see how I can improve what I do. It be cool to quit my second job and just write... but that is a long way off. For now I do my best, and am blessed with some level of results.