Practice, practice, practice. The more practice she gets helping you out -- and being responsible for her things -- the more the habit will be established. Start with small, regular "chores" such as putting away her toys, say, twice a day -- once before dinner, and once before bed. Let her know how important it is for everyone in the family to pitch in, and how much you appreciate her help. If she resists, let her dinner wait while she tidies up, and make the number of books you read before bed contingent on her helpfulness in cleaning up before bedtime. Stick with it, and over time, she'll start to internalize the helpful habit. Good luck!