Comics are not about art. They are about conveying a message in graphic form. Graphs and plots are for accurately conveying data, diagrams are for accurately depicting a system or setup, and comics are there to help people understand an idea. Some of the best cartoonists and comic artists cannot draw much better than wobbly lines forming strange shapes (Figs 1–10). The trick is to find the shapes that best convey the point you are trying to make. For example, you can convey the sense of scale within a system with a single circle and a dot. Use the dot to represent your smallest scale and then draw a proportionally scaled circle to represent the larger scale. This very basic comic conveys a sense of scale better than writing “small” and “twenty times bigger” (Fig 1). As is explored further, it’s not about the smoothness of the lines or the accuracy of the circles, and if you can make a crude shape on paper, you can do what we set out in these rules. Anyone can create a comic, and often the biggest barrier is just getting over the idea that you can’t. With practice, you’ll get better at communicating ideas this way.

While a piece of paper and a pencil are enough to get started drawing, there are also numerous websites that provide comic drawing software free [19] as well as guides on some of the finer details behind producing full comics [20].

The use of comics should make a complicated idea simpler and easier to understand—not harder! Figure out which of your components or steps can be removed or combined in your comic. Comics are like figures in papers; they are best when each conveys one message. Complicated multithreaded comics can look like a “ridiculogram"—a graph with six axes or a Venn diagram with six categories, one of them shaped like a banana (see Fig 4 from [21]). These are graphical strategies that are fun to look at but cannot be easily interpreted (Fig 2). As with the previous example, the comic works best when conveying a simple message, in that case indicating the scale of the system.

Check the science. If your comic has scientific ideas in it, take the time to make sure you have the details right. If it’s mainly just a funny-joke comic, it doesn’t need to be absolutely right. For example, you can add footnotes to comics to point out scientific inaccuracies. But if it’s a comic that is meant to really illustrate a scientific concept for the purpose of education, then it should be as factually correct as you can make it. Including incorrect information in something that is intended to educate is misleading and can lead to misconceptions for those you are trying to reach who may not have a scientific background. In the example of the dot and the circle, no one is going to run a volume analysis on your comic (Fig 3). But they will expect it to be within a by-eye–visible order of magnitude of what you are trying to convey.

Create characters with personality that can guide the reader—what your character wears, how tall they are, what they are carrying. If your subjects are inanimate objects, then add personality by including a face. Humans see a face and easily recognize humanity in objects. The famous example is when you hold a pencil, tell everyone that you have named it Steve and then immediately break it [22]. People will tend to feel empathy for the pencil. Simply naming your shapes can be enough to help people engage with the comic and understand and remember the message it conveys. Personification allows the expression of emotions and interactions between players in your comic that let a story be told (see Rule 6). In the dot and circle example, this can be as simple as giving one of the objects hand-like shapes (Fig 4). Or in a more real-world setting, adding something as simple as googly eyes to equipment can produce the same result.

Comics have a way of going viral (Fig 5), and it’s a good idea to reflect on the possible consequences of everyone in the world reading your comic. (No, not literally everyone in the world.) Don’t punch down: making mean fun of those less powerful or privileged than you is bad form, and you should evaluate with every comic you produce. Maintaining a spirit of fun, self-effacing humor and/or commiseration can often express similar ideas without putting anyone down. Be careful with work-inspired comic ideas. Complaining about your workplace using specific details is simply not a good idea. If you do, try not to make any situation or anyone in the comic identifiable—unless you’ve asked them first or they’re a public figure. It shouldn’t need to be said, but avoid jokes that are sexist, racist, ableist, or most other “ists.” (Marxist jokes may be back on the table.) You should really avoid those in real life as well. If you do get criticized for a comic you’ve posted, take a deep breath, let it out, find a trusted and honest friend or colleague, and ask their opinion. Don’t be afraid to pull the comic. There are rare cases in which any communication, especially those involving social media, has grown to have serious implications for the author [23] and, potentially, the institution they are associated with.

A good comic, like a good scientific manuscript, tells a story. Like a story, a comic has a beginning (the setup), a middle (the conflict), and a resolution (the punchline). A single-panel comic compresses all these into a single illustration, but it may lay out all the elements of the story in the panel (Fig 6). If illustrating a process or mechanism, start with Rule 4 and personify the elements. Then, think about the story your comic is telling—the steps of the process—and how this might be made more memorable by using your characters. What would the enzyme in your comic say if it could talk? You’ve just given the enzyme that ability! All stories have conflict. This can be in the form of an actual villain, a conflict of ideas, an unseen context to the story, or a joke that the reader is likely to understand. It is important that the language you use to help tell this story be simple and legible. Ideally, it should be tested on nonnative speakers. The impact of the comic can be highly reduced if readers don’t understand the dialogue.

As with many other things, the adage “write what you know” applies to comics as well, but don’t feel limited to only what you’re an expert in. Draw from your own experience (paying attention to Rule 5, of course), and if you are comfortable taking on difficult problems or ideas, then go ahead. Personal stories that come from your own experience and emotions can be incredibly powerful [24]. Your comics might be topical, but that’s ok—science is topical. And by bringing something that you care about and understand to a wider audience, you might just communicate outside your subspecialty. Paying attention to concepts you find important, issues that are relevant to you, and interactions you have daily can be a treasure trove of ideas if you pay attention. If you have a comic or an idea for a comic, try bouncing it off a trusted friend or colleague (Fig 7); then, take their feedback and use it to improve your ideas iteratively. It may take time to find what subjects you like to focus on and how you like to represent ideas, and that’s ok. Art, like science, is a continually evolving process, and it is important to find your own voice.

Readers expect comics to be imaginative and to depict ideas in new, fresh ways. A great way to communicate complex or esoteric concepts is to use analogies. Analogies allow the reader to make a connection between something that they can relate to and abstract concepts that may be complex and hard to grasp. An added benefit of analogies is that they often allow for simple variations to make a subject humorous. For example, you can equip a car with multiple “accessories” to depict the process of peer review [18] or transform a dot and circle into an acorn and a squash (Fig 8). However, be careful with analogies because they can sometimes lead to incorrect conclusions about a topic.

One of the most important aspects of an effective comic is clear communication. Storyboard ideas with quick sketches. Lay out the important bits of the comic: where you want the characters, how you want the panels arranged, and where the text will go. This last point, where the text will go, is actually really important and sometimes difficult to do. Experiment with it if it doesn’t seem right the first time. Choose your words. Just like a joke given by a standup comedienne, the difference between a great joke and a dud can sometimes be the specific way that you deliver it and the words that you use. You usually won’t give a talk at a conference off-the-cuff, so don’t do it here either! Test ideas out on others first. Write down a few ideas if you are having trouble. Sometimes the first thing that pops into your head is the best. Other times, an idea needs coaxing and refinement to really shine (Fig 9). You’ll learn to recognize the difference between the two.

No one becomes great at something instantly. Give yourself time and practice often. Sketch at conferences (see [17]), doodle during down time, and carry a notebook for ideas. Learn from others. Read some comics. There are some great ones out there and new ones popping up all the time. Find some that resonate with you and draw inspiration from them. Remember, if you have an idea, you can start without needing to do any drawing at all [19]. Use social media like Twitter, Facebook, Tumblr, and Instagram to reach your audience. Start an account for your comic and it will start to take on a life of its own! Most of all, have fun (Fig 10). Let’s make that a rule.

If you are still reading, take out a piece of paper and draw a circle. Now give it some eyes and a mouth. Now have it thinking or saying something about science. Did it work? Congratulations! You are now a science comic artist!