Oops. I totally called it "mark up" when it is Markdown. haha Well, here is a super helpful blog created by 
https://steemit.com/steem/@xeldal/how-to-liven-up-your-steem-posts-with-markdown
Here is a great blog by 
breaking down how to get paid:
https://steemit.com/steem/@alexc/now-you-ve-been-paid-in-steem-dollars-what-should-you-do
I don't know what to write about!
I hear this one often and I suggest you create an account and spend some time browsing the site. Checking out tags and content you are interested in. Read some blogs from other users in order to get an idea of what type of stuff you can post. But really, it is limitless. I tend to post about radically different things day to day. I sometimes share art, personal stories, articles about mental illness, motivational tips, you name it!
What do you do from day to day? What makes your experiences unique? What are you passionate about? What do you want to share with the world? What are your hobbies? What do you spend time learning about? Do you play video games? Review them! Do you watch movies? Review them! Literally anything you do you can write about. And the more you start blogging the more the ideas come pouring in. Once you open the floodgates you will have no trouble finding inspiration!
Don't expect to get rich quick.
I have several friends whose accounts are worth anywhere from $20,000 to $80,000. They were less desperate than me and kept their steem power invested. But they have also been blogging for awhile. You aren't going to immediately get money or exposure. You have to build an audience. This can take time but the most important thing is to be consistent. Keep posting regularly. Post good content. Don't let your account get cobwebs!
Don't expect instant money. Don't give up after one or two blogs. Just enjoy the community and continue posting awesome content and try to remember that many of the big earners have been here for a long time. Just focus on yourself and your awesome content and you will be earning some spare cash in no time. Chances are, you spend a lot of time on social media already and earn nothing for it. So, why not give this a shot?