OK, so a quick rundown to get you started, because any more would make your head explode ;)

1. Post good content, that you care about, with good grammar. Or at least, review your article before you hit "post"
2. To network with people you can leave replies on their posts. You can also meet people when they comment on your posts. Discord and Chat are great, we'll get to that.
3. Choose 5 relevant tags for your post, THE FIRST ONE YOU TYPE IN THE TAG BOX IS YOUR MAIN TAG, this is where your article will end up. The other tags help in searches, etc. You can click on the trending page and check the trending tags on the right side of the page. These are your best options until you get the hang of things.
4. Break up your text with images and headings. When you go to post there is a link for "markdown" on the right hand side. Learn it. If you still have trouble formatting your posts, use the editer, but you can do more formatting is you learn markdown and type in the code yourself.

Discord

Use Discord Chat to meet other Steemians. Click on a topic on the left and chat away. Please don't leave links to your posts here, unless requested by another user in your conversation. Also, you will see the use of @ everyone, this is mostly for admin use, so please refrain from using it as well.
When in regular discord, not Discord Chat, you can leave the links for your articles in the relevant topics, again to the left. Post promotion topics start under "steemit-trail". If you need help ask Joe or Instructor2121. Please only post the same article in up to 5 topics, usually the tags you used on the post originally.

Steemit.chat

The same general rules apply to chat, you can search for topics on the left, enter the topic chat and talk to likeminded people. Read the rules at the top of the topic to see how the chat room should be handled. You can post links to your post in the topic rooms, but usually no more than twice. There is a "post-promotion" chat room that you can enter to post the links to all your articles. General chat is the same as Discord Chat, no links please, just talk.

I hope this helps!