I don't sell anymore either, but when I did (ha! I'm sounding a lot like @Aproned Artist, aren't I?), I would bake as close to delivery as possible, while allowing enough time to decorate on the tail end. I typically would try to make the entire process take no longer than a few days, and would enlist help (one of my employees) on the decorating end if I expected that part to take longer. I always made my cookie dough in advance, froze it, and then baked it off to order. Still do.
@SugarDotCookies also has an online course about planning your baking and decorating, I believe, so you might check that out. She might also have some quick tips to share here.