Welcome to Steemit! I started here months after Steemit was opened to the public. I hope that you will find success here, but in order to do that, you'll need to do a few things. There are essentially 2 sides to Steemit: posting and curating.
Last updated 3/28/19.

Posting

The creation of new messages is a big part of it.

Post regularly, sharing good quality content that you have created.
Include at least 1 image in each message that is strongly related to your theme.
Use all 5 tags (below the editing area is the field for tags). If you're new, use "minnowsupport" as one of them. (Minnows are people with very low "rep" - anyone new, in other words, plus trolls, flamers, con artists and a few unlucky souls.)
If you don't see a tag related to your topic, create one by putting it in the tag field with others!
Start sections with a title.
Organize your messages well into paragraphs.
Use proper grammar and spelling.
Use some font styling and other styling elements to improve the appearance.
Please do not post someone else's content as your own. That is plagiarism and there are editors who will flag your content (including me) for theft.
If you share something made by someone else, give the creator credit and add your own thoughts about it, like a review, analysis, exegesis, etc.
If you post someone else's work without anything from yourself, please turn off payment and link to the source. You do not deserve to be paid for that and, again, some of us will flag you if we think it's theft. I don't "like" or subscribe to people here, YouTube or elsewhere who only repost others work as their own.
If someone comments on your post, thank them and respond. Don't be rude! It is okay to disagree politely, but Steemers don't like it when you troll, flame or otherwise provoke us!
If someone likes or resteems (reposts on their blog) your work, be sure to go to their blog and find some posts to like and/or resteem.
After you've posted the message, go back to it, then like and share it!

Resources for Styling

Adding Line Breaks and Lines on Steemit
How To Make Tables (and Proper Code Nesting) on Steemit
Using Lists on Steemit
How to "Quote" on Steemit
How to Left/Right Justify Contents into Columns
How to Center Your Text, Links and Images on Steemit
How to Change Your Font Style on Steemit
How to Use Headers on Steemit
How To Resize an Image on Steemit
Adding Emoticons & Other Icons Using UTF-8 Decimal (Base 10) HTML Codes on Steemit
How To Expose and Neutralize HTML and MDL in Your Steemit Posts
The Trouble with Spacing and Tags on Steemit
Using Special Text, Characters and Symbols in Your Posts (Hint: Unicode)
Easy Way to Link Your Steemit Posts (Codes & Examples)
How to wrap your text around your images in Steemit post. Easy! (Codes & Examples)
[How to see the complete list of people upvoted your post.](How to see the complete list of people upvoted your post)
Using Special Text, Characters and Symbols in Your Posts (Hint: Unicode)

Promote Your Work Elsewhere

An important aspect of this business is self-promotion, and the easiest way to do that is to "share" your work elsewhere. After you post a message, make use of the buttons on the bottom right

to share your work to Facebook, Twitter, Reddit, LinkedIn, steemd.com, steemdb.com, busy.org and you can get a custom link to share it anywhere else you can think of, including in your comments to other Steemers! :)

Curating

The act of looking at other people's messages and responding to, liking and resteeming worthy posts. This is important to help you build a network of Steemers who support you.

Take time to look at tags you're interested in and read through them to find posts you appreciate it.
Any worthy posts should be liked, resteemed and/or commented on.
Relationships are important. Start conversations with other Steemers, and be kind and polite to build up a following.

Consider Joining a Voting Group

There are many groups where you pay in a small amount and give some of your access to the program behind the account so that it can upvote posts by everyone in the group. I've never been in one, so I cannot recommend any, but I do suggest you do research to make sure that their algorithm is built on the right rules, and that you'll get a good deal because the owner of that account certainly will!

Consider Steem-Related Sites

There are a number of unaffiliated websites that offer services that are a complement to Steemit, such as dTube. Steemit doesn't seem to recommend any, doesn't seem to be affiliated with them, and warns that if you give access to your account so that a site can post content to your account, something bad COULD happen. You should have safeguards set up (such as a friend to restore access to your account if it's stolen) to reduce any risks you might incur.

Use Unrelated Sites

Alternatively, just use other websites and post links to your work there (e.g. videos: Vimeo, Daily Motion, YouTube; programming: GitHub, CodePen; writing: GitHub, Wordpress; music: Free Music Archive, SoundCloud; etc.). You won't have to give special access and there are certainly plenty of sites which allow you to monetize your efforts.

If you have an article you think should be on this list, give me the link in a comment with the title. I will review it and if it actually works and is useful for editing/formatting, I'll add it to the list, then resteem and upvote you!
Format: [write your title or description here](put the article URL here)
Example for a comment:

Hi there!  Please look at my article: [Adding Emoticons & Other Icons Using UTF-8 Decimal (Base 10) HTML Codes on Steemit](https://steemit.com/editing/@reveurgam/adding-emoticons-and-other-icons-using-utf-8-decimal-base-10-html-codes-on-steemit).  Thank you! I hope you like it!