One of the hardest decisions I had to make was what business to start. Like many people, I am multi-passionate. This became evident when I changed my major in college MANY times. It amazes me that people expect you to know what you want to do for the REST of your life when you are 18... HA. I couldn't decide if I wanted to focus on healthy eating and real foods or art and jewelry. Then after college I got interested in fitness, then psychology, then spirituality, then entrepreneurship itself (and the list continues to grow).
Here is what I learned... it doesn't matter. As long as you are truly passionate about the subject, then it doesn't matter which subject you choose. Picking jewelry didn't mean that healthy eating, fitness, and spirituality were no longer a part of my life. I may monotize my craft, but I still enjoy cooking real foods, working out, and pondering the big questions in life. In fact, working for myself allows me to make time for these things because they are all a priority to me.
I wasted far too much time going back and forth on which direction I should go. In fact, I tried to start a health blog but was so bogged down by questioning if I made the right choice that I couldn't focus all of my energy on it and I burned out.
Second guessing yourself will stifle your creativity and energy.
My advice... Just pick a subject (as long as you are passionate about it) and see where it takes you. You really won't know if it's going to be the right choice until you get into it. Just dive face first and allow yourself to be consumed by it. Write about it, talk about it, photograph it, share it, dream about it.... just see where it goes. No doubt you will learn from the experience and will be well on your way to refining and morphing your subject into something that is sustainable, fulfilling, and authentic.
If you find yourself over-analyzing and desparate for clarity on which business is right for you, I recommend picking the one that will be the easiest to get started, because starting is the most important part. Just remember, you aren't committing to anything for life. You can always evolve your business and it may end up entirely different over time. Don't be afraid to bring your other areas of interest into your work, social media, or blog. The more authentic you are, the more you are going to connect with people who can really relate to you and will more likely become a lifetime fan and advocate of your work.