By drawing them, silly.

How about a lottery? Open commissions for 24 hours (or whatever), then put all the requests in a hat and randomly choose however many you feel you can do without stress.

i think it should be a first-come-first-serve, with exceptions for people who offer more pay and for people who have characters you'd enjoy to draw.

Hmm... it's tough to say whether first come first serve or first most interesting idea would be best...

This is just an idea, but you could have separate slots for different types of commissions. You could have some sketch slots, some clean-lineart slots, and then one or two colored slots. It might help you to choose which comms to accept.

You don't want to get swamped, but you don't want to be unfair or biased.

How about you tell us about 2 or 3 hours ahead of time, that way those of us without immediate access to funds would be able to get ready, then list your commissions for a short time (about 6-10 hours or something), then close them, and do the ones on your list, then begin anew once you finish the list.

Open slots for them and do them when you feel like it. Just don't tie yourself down by getting paid in advance. At that point you either have to do it or return the money and there's always the chance that the person commissioning you will get impatient and ask for a refund.

First come first serve is terrible for things like this.

First come, first serve.

Isn't that how most people do it here?