While you're waiting for the book, here are some short-term suggestions I have for you.
Make sure that your action lists are clean and contain true next actions on your projects, not vague undoable stuff or mini-projects in disguise. That will cause you to go numb to your lists. Think of your actions as bookmarks - you only need the last place where you left off on a project.
If your lists are in fact clean as they should be but you have too many from which to choose, it's time to prune them down to a manageable size. Shuttle some of those projects to your Someday/Maybe list and remove the corresponding next actions from your action lists.
Another thing you can do with a large action list to prune it down is to identify actions that would require < 10 minutes to complete. Flag them in some manner and go on a short marathon session and just do them. That cuts the list down to size. I frequently do that with my @Home list; there are over 45 items on it.
Finally, if I'm really hung up on priority decisions, I choose a context and starting with the oldest item on the list I examine each item until I find one that I have the time and energy to handle. Then I just do it. Is it the best thing for me to be doing right now? I'm not sure, but it's better to get something done than to fret over priorities and get nothing done.
Best of luck.