The publication process for comic books is quite similar to that of other literary publications, however, most up and coming comic book writers don't realize all the other elements involved. 

Let's begin with the basics that one must know when it comes to publishing your work: 

1. You don't need an agent, but it would be great if you had one. Most agents have connections that range from the smaller publisher to bigger publishers in the industry. 

2. Publishers aren't heartless, they love good stories just as much as anyone, but they do put what's best for their company over potential unless you're an already established author. The biggest thing they look for is if you're an author that can make them money. 

Now the basics that comic book writers should know before submitting their work: 

1. Logline 
If you don't know what a logline is then you should probably keep reading. 
A logline is basically a sales pitch, it sums up your story in one or two sentences. It is the most condensed version of your story, a summary of a summary. 

Your logline should explain the following: 
- Who the main character is or who main characters are
- What they want or need to do 
- What is holding them back (the conflict) 
- What the consequences are 

2. Synopsis 
The logline sells the idea and piques the interest of your audience, while the synopsis serves to provide satisfaction to your audience by divulging a bit more information. 

Your synopsis should have the following: 
- A deeper explanation of your main character or characters 
- A slightly deeper explanation of the main plot (without giving everything away)
- Should be under 300 words (unless you plan on making multiple issues or volumes)

3. The Outline 
Similiar to manuscripts for novels and books, the outline serves the purpose of telling the entire story from the beginning, middle, to the end. Short story outlines should be no longer than a page. For multiple issued stories the outline is a bit different. One page is equivalent to one issue. 

Your outline should have the following: 
- It should reveal exactly what happens in the story
- Leave no stone unturned 
- Note anything to do with the plot and characters 
- Never ever leave the conclusion on a cliffhanger or as a question 
- Know your ending 

If you're lucky enough to be published then you should know the consequences of publication. So, let me talk about that. 

Post-Publication information: 
Much like television series, comic book or graphic novel publishers may sign you on for multiple issues. However, just like in television, you could face cancellation if your comics aren't selling enough. That seems harsh, but that's just how it is. Time is money regardless of whether or not you're trying to publish a novel or a comic book. 

You might be wondering how you can avoid this, but there isn't a real way to avoid this. Sometimes things go out of fashion and people lose interest. Nevertheless, there's a way to prolong anything. 

Always know your audience. What demographic are you trying to target? Do your research, know what's in and know what's out. If you ever face cancellation remember that you were lucky enough to have gotten published and remember that there is always another chance for a brand new story to tell. Most of all, never count your audience out of the equation because they give your stories life and give it a chance for a revival. I honestly can't count how many times the Justice League has been incarnated.