Mindset pieces can be popular, but use them sparingly. Most new content creators make the mistake of thinking that their personal philosophy of fitness/health/etc. is what people really want to read (it isn’t). It will be when you’re big, but right now you should be working on content that
Don’t worry about trying to get writing gigs with the big fitness websites/magazines at this point. Those jobs will provide you with some cred, but they will take a ton of time (also, those guys will ask you to write, not the other way around). When you’re big enough, they will come calling.