Has anyone dabbled in Self Improvement successfully?

I've been spending the last couple of months researching internet marketing and trying to dive into a niche. I want to choose a topic I'm experienced with and passionate about, but one that also has the potential to earn money if I dedicate myself enough. Self improvement is something I've been practicing for years now and I've solved a ton of my anxiety and social phobia issues without much therapy (I went to two sessions and quit because of the cost).

This last week (and yesterday in particular), I went through the ringer. I was delivered blow after blow in many different aspects of my life, but I've maintained a very happy and optimistic outlook nonetheless. This gave me the inspiration to write a book about how life can deal us a bad hand and what we can do about it to stay happy. I've always felt I could help people with their anxiety, depression, motivation and general life outlook, but I wanted to prove it to myself first. I feel like I've reached that point and can make myself an authority in this realm, so I was thinking about making a website for blog posts and articles, as well as making Youtube videos about some of these topics to drive traffic (among other methods).

This is a niche I'm personally passionate about, and I think I can make that shine through without coming off as just another salesman. My only inhibition is, most of the self improvement niches I've seen target relationships and dating. I want to help people with their issues, but I also want to make it a business so I can get some hands on experience.

Has anyone had success in self-improvement outside of dating and relationships? I'm looking to make people feel good about themselves and see they can improve their life like I have. I don't want to sell gimmicky courses or products that don't work. That just isn't my style.

Thanks in advance, guys!