I've been reading Unscripted by MJ DeMarco again lately. In the book, MJ reminds us that the key to a successful business that has pull instead of push - meaning, you don't need to rely on advertising to get customers because customers come to you because you have a kick-ass product they are willing to pay for - is productocracy. Your product or service adds value to people's lives, so your customers recommend it to their friends, who recommend it further, without you having to pay for their warm opinions.
Step 1: stop being a consumer first, and start being a producer first.
Step 2: produce something of value, and offer it to the marketplace.
Step 3: wait for feedback.
Step 4: use the feedback to make your product better.
So basically: doing what you love and following your passion are terrible advice if they do not lead you to a place where you provide value, give people what they want, or solve their problems. It's a better bet to start with productocracy - finding a way to make people's lives better - and notice that the positive feedback and the value you add in the world is the thing that makes you passionate and makes you love what you do.
In a nutshell: this changes everything.