The best way to take on requests is like this.
1. Create a post saying requests open (include whatever/do's don'ts like if you draw feral,furry,humanoid)
2. Let people comment their requests.
3. Check out their OCs and find ones that you like
4. TELL NO ONE who you are drawing for. EVER. Just draw what you want in secret
5. Post up what you drew. The end
There's a few reasons that this is a pretty darn good way for request taking. The first is to avoid the people who Harass over not getting their free art in .02 seconds. Never say "I accept this request" because your sure as hell going to have to deal with someone like this probably 90% of times you open requests if you accept requests and make a queue. I guarantee it. This kind of person is stressful as heck, makes artist not want to draw ever, and good chances you'd never want to take on requests again after someone like that. I'm sure there's a number of folks who can tell you the times someone who wanted free art messaged them every single day "is it done yet?"
Second reason, Avoiding the "You didn't draw it like I asked. Change it." people. Requests... really shouldn't be hard work. Most people open requests for practice, to doodle, or because they are bored. The last thing those artists want is for a simple doodle to become a project because the leg wasn't in the place requester wanted it on the WIp or something. Don't offer Wips and don't offer after-post changes. It's free art, and it shouldn't be a source of stress and a time consumer. This type of person doesn't happen often, but when it does it's such a tornado.
Third reason, Dear Artist, you can decide to not do any requests at all if you suddenly don't feel up for it. If you don't create some Queue and tell no one who you picked to work on, then no one can complain if you do ten, one, or none of the requests. Doesn't it suck when you lose your steam but promised 3 other people art? Avoid a queue by not "accepting" any requests. Stress is the worst thing for an artists and to-do lists are the absolute worst when you are getting nothing in return out of it.
One free request you've promised but lost interest in or are being harassed about will eat at you and effect your time in the art community, your artwork, your commissions, your sleep, etc. Avoid the nervousness and fear of logging in or the fear of seeing that you have a note/comment notification. Don't create a "request Queue". Draw only as much as you want and tell no one.
Wrote this because I often see so many journals of artists declaring they'll never take requests again because of their awful experiences.