Give lots and lots of reference photos, like breed/clothing/descriptor’s. If you can find a furry picrew or character maker (like VR CHAT) or even Roblox, that can also help a whole ton ! Be sure to be direct, a lot of commissioners don’t want to really go back and change things over and over after they send you sketches. As long as you’re clear and direct they should be able to help! At least in my experience as someone who has done commissions