A graphic novel is pretty much like a paperback novel except that it is told with pictures or graphics (hand-drawn images). The script of course is an integral part of the whole thing, besides, you wouldn't understand whatever is going on, on the pages, save maybe for the action scenes in some panels. All in all the core of your graphic novel should be the whole plot and how you tell the story, the graphics are just a supplementary element that enhances the story. In fact they serve the purpose of literally visualizing the character as there are times when words are not enough to describe someone or something.
Plot
With millions of stories that have been told over thousands of years in many different languages, it is almost a rare thing when someone is able to come up with something new. But you can still write a new story rich with surprises and twists as long as you do not compare your story with someone else's work. Originality is a critical aspect in creating a graphic novel. It may also be best not start your idea by thinking in what genre' you will write it on, because it gets cramped up in your head thinking about a plot of action, adventure, thriller, horror, drama etc. Instead start your story by picturing the moments of it in your mind. You can think about a vampire story where it starts with a mysterious murder case, then insert a climax where hundreds of vampires chases the protagonist and ending it with a bang - a battle between the champion of the story and the evil villain vampire in a lopsided fight that favors the villain, until that one instant when the good guy exploits his vulnerability and wins the fight by virtue of pure chance. You can then put your story in the corresponding genre' that it belongs.
Graphics
This part of your work will take a lot longer than creating the story and plot, especially if you're an inexperienced beginner in drawing. Basically what you would need to do is learn to draw, there are a lot of online course on this subject. You can also buy a tutorial book or CD's and learn to draw comic book characters and background in a matter of months. Learn some digital graphics tools like photoshop and corel draw because they can lighten up the load in completing your work at least 30% faster, especially in coloring and clean up. As much as possible come up with original characters (i.e. looks, costumes, clothing, hair and eye color, facial structure etc.) and make your panels more dramatic to enhance the emotions of the readers with each scene.
Plot
With millions of stories that have been told over thousands of years in many different languages, it is almost a rare thing when someone is able to come up with something new. But you can still write a new story rich with surprises and twists as long as you do not compare your story with someone else's work. Originality is a critical aspect in creating a graphic novel. It may also be best not start your idea by thinking in what genre' you will write it on, because it gets cramped up in your head thinking about a plot of action, adventure, thriller, horror, drama etc. Instead start your story by picturing the moments of it in your mind. You can think about a vampire story where it starts with a mysterious murder case, then insert a climax where hundreds of vampires chases the protagonist and ending it with a bang - a battle between the champion of the story and the evil villain vampire in a lopsided fight that favors the villain, until that one instant when the good guy exploits his vulnerability and wins the fight by virtue of pure chance. You can then put your story in the corresponding genre' that it belongs.
Graphics
This part of your work will take a lot longer than creating the story and plot, especially if you're an inexperienced beginner in drawing. Basically what you would need to do is learn to draw, there are a lot of online course on this subject. You can also buy a tutorial book or CD's and learn to draw comic book characters and background in a matter of months. Learn some digital graphics tools like photoshop and corel draw because they can lighten up the load in completing your work at least 30% faster, especially in coloring and clean up. As much as possible come up with original characters (i.e. looks, costumes, clothing, hair and eye color, facial structure etc.) and make your panels more dramatic to enhance the emotions of the readers with each scene.