For starters, I recommend that you read Cyrin journal detailing this thing. Forhttp://www.furaffinity.net/journal/3922694/

So here is my addendum to this, apart from proper stream etiquette. (eg don't let people feel like they don't belong simply because they are not a close friend of the artist or the people in here.)

"How to contact customers and vice versa."
It is important to note that I will not be giving any names of bad examples to protect the irresponsible. Anyways, here are a few examples of what NOT to do, and WHY you should NOT do them.

I've seen several people who only communicate to certain users that they're open for commissions. I understand not wanting to take business from certain people who have a proven history of scamming others (Such as Andrew Rinaldi - the only person I will refer to by name here.) but I have seen a lot of people who use multiple galleries flat out not communicate to the people on them that they are open for commissions. I actually didn't know that one artist I watched on deviantART took commissions for average every day people until one of my friends said the only way to contact him was via a note... on FurAffinity
...which he had under a COMPLETELY DIFFERENT USERNAME.
Note that neither his deviantART, SheezyArt, or InkBunny page included this information. And this wasn't something similar like how a user may be "TyeMyShoe" on deviantART but "TyeMyAShoe" on InkBunny. This would be like if I registered an account on Weasyl as "Wolfmoonfourtyseven." You'd probably think "...who ARE you?!?"

I encourage people to use multiple sites - Look on SoFurry sometime, will you?
You'll notice there are people using this site that aren't on this site right now. In fact, there are a good number of people who use SoFurry and ONLY SoFurry. (And in fact, I and my friend Tera have been attacked verbally for not only using SoFurry.) Some of these guys may actually respect your artistic, musical, or literary talent. Using multiple sites is simply called "Getting your name out". You don't go to just one publisher with a novel to publish. You don't submit your pictures to just one gallery. You don't run advertisements in only one magazine and hope to sell your product. GET YOUR NAME OUT THERE!!

So I encourage you to say, open up an account on sites like InkBunny, SoFurry, or whatever. And at least try and communicate that you are open for commissions or not - you might lose a lot of potential customers simply because they do not even know you exist, or that you actually do take commissions to average every day people and not a close circle of friends.

One of my suggestions? Use a system that can allow everyone from every site (because they may only use one site, like the aformentioned SoFurry-only clique, the InkBunny-only clique.). One way to do that?

Emails.

This is one reason why I have commissioned jakkal and virmir, as they make it very easy to contact them. Virmir doesn't say "Commissions open" on one site and not the gallery on Weasyl he forgot to update - Virmir redirects you to his site with a way to contact him. Similarly, Jakkal tells all potential commissioners that if you want a slot, email them since that's what they check first.

They likewise also include detailed instructions on what to put in the header, so you don't get lost in a bunch of spam messages or automated "You have received a tweet from blablabla", etc.

When I heard people say "rawr rawr rawr, FA's down and I have every right to bitch because I rely on the site to make a living"... I simply ask myself "Why on earth don't you use email and other sites to get your name out?"

Another way that I have found that works to get commissions out? Google Docs forms.

This is one reason why I have commissioned from aggro_badger and sonsasu , and intend to do so again in the future or direct others.

Aggro Badger has this down to a tee. Similar to virmir, he has a system in place - he created a docs form wherein you include information such as when you are available, whether or not you "need" to be in the stream, and how to contact you. He then will have himself or Talosar contact you after reading it to tell you whether or not it's accepted.

Similarly, Sonsasu requests an email in which he can send you the files as well as the paypal invoice.

It's simply more reliable than asking people to only contact you on one site. Especially if you are limited with the slots you have available.
"Whoops - I completely forgot to check my deviantART so I guess those guys will just have to wait a week even though they sent their information before I read all the notes on my SoFurry!"

So yes, it can help to send notes on sites... but really, if you have an email, then you don't have to check every single site for a person asking if you are open for commissions. It's simply a lot more efficient that way - and I wonder why more artists don't do it.

-Keep your information on all sites current.
I found one artist advertising on SoFurry, and they simply said "Email me at Blablabla@gmail dot com." I emailed them...
...and got a very rude email in response saying "CAN'T YOU READ? I AM NOT OPEN FOR COMMISSIONS!" (Language toned down.)
They may ahve been frustrated due to people on SoFurry contacting them, but given that their SoFurry page had been updated with new art, they completely forgot to take down their little advertisement on the SoFurry marketplace, and their Weasyl had "Commissions: open". Really, can you blame people for thinking you're open for commissions when you didn't update your site?

Another time, I saw the opposite - I saw one person wonder why nobody commissioned them. A few clicks later, I noticed that their "Commissions: Open" page that they used to keep track of their commissioners had still said "Commissions Closed" on it, since they had closed commissions to keep themselves from amassing a huge backlog. Oops. Not only that, it was buried under a pile of their personal art and commissions. So... how were were supposed to know they were open?

Some artists put a link to the "how to commission" or their docs in their profile. Some sticky the art in question (usually a price sheet). Some link to a google doc where they have a table with all the current in-progress commissions, like my good friend kitsunekit

You seriously need to keep track of your work. Which leads to the next point:

-Keep track of your work
One of my friends decided to write off an artist since they had literally forgot their work. One time I saw an artist open up for commissions on a slot basis, take slots, finish three of them, vanish off the web for a few weeks (or less), then open up again with the other two people who had gotten their slots confirmed left behind. :/ This happens a LOT with Livestream commissions - seriously, one rason it took so long to commisson one artist was you had to be online in their stream, and the streams were SO active I saw someone trying to contact them get drowned out. Similarly, one person was simply asking for a "Do you have a commissions sheet?" only to be drowned out by random RPing and people having full-blown cybersex inside. :|

This relates to one of Cyrin's points that was made in the article - Limit how much work you can do. Seriously. I was actually told (by Inflatophin, no doubt) that a certain artist I wanted to commission had art that was commissioned in 2008 still owed and was incredibly disorganized. They would take commissions with payment up front, spend the money, then open up for more commissions before they were finished. They were also so disorganized they needed a poke to know who needed what, and some people who made their commissions AFTER certain people got their stuff BEFORE others.

This has happened with so many artists. :V I know not all of oyu guys are doing this for a living, but really, that's no excuse to be so ungodly disorganized.

-Don't engage in "Microsofting"
You know who you are. ;) I'm not naming anyone... but trying to steer people to certain sites by only offering commissions over those or only posting sketches and thumbnails isn't advertising the site - it's just being a douchebag. :) And in fact... I feel less inclined to commission you.

If you attack people for their choice on where to hang out... then you're just being a douchebag. :) Using multiple sites with a certain preference (eg, where your most active commissioners hang out, or your own) is advertising. Cockblocking and frustrating people into going to another site is just being a douchebag. ;) So is attacking others for not using one site.

In other words... don't be a dick.