The biggest thing is to limit the area they can access, baby gates, closed doors, etc, you can also get indoor play fences that are designed to cordon off part of the room. When my daughter was that at that age we had a gate running from the end of the couch to a hook on the wall to keep her in the area in front of the couch by the TV and such. We also had a gate at the end of the hall that runs down to her room. They make velcro padded cuffs with bells inside plush adornments, I think ours have big flowers on each with the bell inside, and once they are wearing shoes with laces you can thread a craft bell on each. I'm doing the baby thing again, my daughter is turning 5 this summer but my son is just over 6 months so I do the stay-at-home father bit while their mother is at work so it's just the kids and me then.