Children need to know the rules before they can care for themselves. But they also need to know why a rule is important. Ask your child why he thinks you have a specific rule. If a child knows you don't want her playing behind the garage because there is broken glass there, she is more likely to remembers the rule and follow it. Allow practice time for children to act out potential situations.
Young children learn best by doing an activity.
Pretend there is a fire and let your child show you how he would get out of the house. Have her practice using the microwave to fix a simple snack. Set up a trial period. Presenting self-care as a temporary arrangement lets children know they have a choice not to continue if they find themselves uncomfortable staying home alone. It also allows parents to more easily end the arrangement if they feel the child can't handle the situation.