This is a topic that has more answers than successes. I often tell parents that “go clean your bedroom” is a really daunting task and to look around their bedroom and think how they would feel if someone told them to clean it.
Children (and maybe all of us) do better with specific tasks—put your dirty clothes in the hamper, make your bed, etc. Much of the time “too much” is the biggest problem. Too many toys or shoes or clothes. Just thinning stuff down will help a lot.
Try to model the behavior you want. Hang up your clothes and coat.
Have simple places to put everyday items. Walk your child through their chores rather than just keep yelling at them about their chores. Concentrate on every time they do what you want them to do.
Comment on how peaceful a clean house is and how nice it is to find stuff where you know it is suppose to be.
Most experts agree that tying allowance to chores is not helpful. We do chores because that is part of living and part of being in a family. Allowance is a chance to learn how to manage money and is most appropriate starting around 8-10 years. This age is late to start with basic self-care that is the primary reason for chores.