Asking your children to be creative comes with a huge cost. This cost lies in ensuring a lot of mess to your home. Now, someone who has a couple of children wouldn't worry for the child's habits. But, someone who has a lone child would want their kid to develop a good creative habit, because they may not have anyone to look up to.
One thing that can be really helpful in this regard is to not worry about the mess when they are being creative. Let them be creative as much as they want and you can take a backseat here. So, one way to ensure that there is no mess is to have ziplock bags positioned in a way that can help your child add dollops of paint on it to garner his/her creativity.