It's a shame the bounty has been paid out already, because this is a reply full of good tips.
Personally, I like the watermark idea - I haven't used that trick before, so I steal the idea ;0)
The last two paragraphs in particular have made me curious about what you have been doing in the past. I'm guessing you're not new to some kind of marketing: you have a mailing list, but it's also your choice of words.
Anyway, I can only agree the things you say. An appealing photo, a nice layout, the right tags... all very important factors. And it is absolutely true that on here, you are your brand. Networking is extremely important, maybe even the most important marketing technique of all. Once people get to know your name and like the things you say or do, they start looking out for your posts.
Thanks for this interesting reply
All good, I just wanted to contribute :-)
Another idea for marketing is if to add your steemit link with or without a kind of catchy logo in the email signature. So every single email you send professionally or personally is also promoting your Steem profile.
I've worked with a communication agency before, not as a marketer but I still learned some tricks and ways of thinking. Also sitting with designers for marketing project is helping with understanding stuffs. I have a mailing list and also have some email marketing automation going on things like if one of my newsletter subscriber goes to a specific page of my worm farming website, then it will trigger an email to advertise for a worm product etc... if they click on it, it will send another one two weeks later blablabla.