I'm 100% in on content marketing for my business and after roughly 2 years of dabbling, experimenting and honing my skills I think I sort of get it.
For anyone starting out, all the common advice is true:
1. Create valuable, original content. This can be VERY specific to a VERY specific niche. People LOVE reading about how the sausage is made.
2. Go where your audience is. Took me a while to figure out. For me that is specific sub reddits and HN. Twitter to a lesser degree.
3. Keep a schedule. Once a week, once a month. Whatever works for you.
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4. Get a tool / platform that removes obstacles. Probably why Medium got so popular. It makes writing and adding pictures really easy. No subliminal / subconscious blocks on writing that next post. I use Ghost now. Same experience, just private. The cost is trivial if this is your only marketing outlay.