This is stuff I personally always keep in mind when I recieve commissions. Others may probably do this differently. But I personally find this the best way for me:
well first off, the most important part is to be able to recieve and give money safely online. Most people use Paypal, since it’s still currently the most easy way to transfer money internationally.
A commission is a “paid request”; the commissioner does not hold copyright of your picture. This means that even if you drew their OC, you still have the full copyright ofthe picture; your commissioner does not have right to use the picture commercially for their own profit without your permission. This is VERY VERY important to know about, if the commissioner wants a CD album cover or a cover for their book, you might wanna raise the price A LOT more. Because giving up your copyright on your drawing for $5 and later discover what a fortune the cmpany has made out of it, is the last thing you wanna experience.
Make a list of slots.
Don’t do the mistake of accepting all commissions coming at you in one go. You’ll only stress yourself out if you end up having 10 pictures to draw and there’s people waiting for you.
it’s really good to know your own working process.
How many hours, without breaks, would it usually take you to finish a picture? One hour? five hours? It’s good to remember that time is money after all.
Make sure people know what they will pay you for.
Show examples of how you artwork looks like. If you don’t have that much to show, then I’d advice you to draw more often and build up a decent gallery.
People pay you not only for the picture, but also for the TIME you spend on the picture.
Make sure that even if you have low prices in the beginning, that you’ll get paid that matches up the time spent on it. Maybe you have a starting fee of $5 but for every hour (excluding breaks) you have to spend on the picture, you add $5 more to the price.
When your art progress and you feel like you’ve improved quality wise in your artwork, you might wanna raise the price to $10 and so on it goes.
Make sure you have a good communication with the commissioner! This one is the most important one. If something happens that might delay the payment for the picture, or you cannot finish the picture in time. You must be able to contact the commissioner. You don’t wanna end up in a situation where you’re waiting for the money to come but you’ve lost the customers email or something like that.
Make sure the customer actually can pay you. A lot of people talk about artists who don’t finish commissions even after getting paid, but it’s just as common the other way around that the artist work hours for a picture, only to later notice they never got the payment for it.
I hope this helps you out a bit.