Relevant Productivity

I'm participating in several Big Bangs this time, and I'm having various problems with my artists. I think this applies both ways, though: author to artist, and artist to author.

-Introduce yourself! auroraprimavera was my first ever Big Bang artist. The first email she sent me was an introduction, and lo, we got on like a house on fire.
-Respond promptly! Even if it's to say you can't do [x], at least then your partner knows where you stand.
-Keep in touch. If you have a problem, let your partner know, so that if you suddenly disappear offline but you'll be back in time, they don't contact mods going "help! my artist disappeared!". If you don't have a problem, just let 'em know you're still around and doing your bit.
-If someone sends you their latest draft, it's nice to respond and let them know what you think once you've had chance to read it/see it. One of my artists received my draft almost two weeks ago and there's been silence since. Silence feels ominous, to me...
-Work together! Don't spring a massive plot change surprise on your artist two days before the deadline.
-If you promise to do something, deliver. If you promised a rough draft by Tuesday, follow through!
-If in doubt, ask.

What other advice would you have about getting on with your author/artist? My main problem has been total lack of communication.