I would like to know what strategies would help me create a monthly revenue stream for a spiritual blog. I will do general motivation (like Brendon Burchard or Tiny Buddha). Creating a passive stream is something important for me to get some form of predictability in finances.
As far as creating a "passive stream" goes, some of the other answers are very good. Affiliate marketing, premium content, etc. can certainly help you to do that.
However, if you really want to take it to the next level, I think you are in a position to forego the "passive" thing and put in a reasonable amount of work to make some real money.
I am talking about becoming a coach or guide.
Call it what you want: life coach, spiritual adviser, etc. Work out a system so that you can consult with people on a regular basis, focusing on the spiritual truths communicated in your blog, and help them to achieve their goals in life. Charge $15,000 to $25,000 per year. Take on dozens of clients. That may sound like a lot, but if you can help people to completely revitalize their lives, it is peanuts.