Drawing assets is a huge time sink for me. I've spent some months dedicating myself to get better at it. While I can now draw some assets that's not too bad, the problem is that it still takes a way a lot of time I can be using for coding. Taking cool art and making them interactive feels really good, but drawing the cool art from scratch is very tiring for me, and leaves me more vulnerable to burn out. 

So I'm just curious: All artists, whenever someone opens up a new topic anywhere for getting a team together, what compels you to join them? What type of projects do you enjoy working on the most? 

Also, let's say I did find someone good at art and could make nice assets and animations - what actions should I avoid that typically annoy artists? And what are some things coders and game designers can do to make the job of an artist easier? 

What the things you liked the most during your times working on your favorite cooperative game projects, and what did you like the least when you worked on your least favorite ones? 

Discuss pay directly, address your budget, or your model of payment ASAP, whether you need a volunteer slot filled, paying per piece, per hour, budget, rev-share, etc. Also discuss things such as ownership of the assets, in some countries and some states emails can be used as legal evidence in court, you may want to look into a contract specifying everything to protect you and the artist.

I can only answer bits and pieces of your questions based on my experiences, but as a coder/designer to make the artists job easier, learn how to use art in any format they send, for example if they are making you 2D sprites, you will probably be receiving sprite sheets, learn how to import sprite sheets in whatever engine you are using, so that you don't have to look like an idiot and ask the artist to export every still image seperately as well as sending you animated versions for actions. Learn everything on your end, learn basic photo editing incase you need to make minor adjustments, be as clear and detailed as possible about what you want/need so you don't need many (if any) revisions from the artist. I personally like to give artists the freedom to make their own ideas come to life, i'll give a brief prompt of what i want, size, format, etc, theme, color pallet, but i don't want to micro-manage and get too particular about my vision, i want the artist to do what artists do, and make art.

Make their job as easy as possible by either knowing exactly what you want, sketching up concepts to show them so they can understand what you want, or keep it open ended and trust them to make what you want, either method can work.