I think it would be great to see more of how you do your work }=3

Trello is useful when you have a lot of scheduled commission slots, generally on many months in advance, but it demands regular updates to keep your clients on track. I saw many artists using one but who stopped to updating it, maybe because it didn't have much interest since they were never taking more than 5 or 10 slots every once in a while, or simply because they were too lazy to do it :P

That all depends of the amount of commissions you do, if you really do a lot and even working progressively on several pictures at the same time, then considering getting a Trello could be a good idea, if you don't do that much of commissions like I said above, then I don't think there's much interest at using one.