1. Only wash them if they're actually dirty. check for stains and smells and otherwise the wash can wait for a few wear and their threads will thank you!
2.Use a steamer. A steamer is a bit less hard on their clothing than an iron and you can get one for next to nothing at your local store.
3. Use the dryer sparingly. If your child have a piece of clothing you just LOVE and want to last, dry it for only 5-10 minutes in the dryer to get the wrinkles out then hang dry to keep colors vibrant.