Always watch your kid – even when surrounded with people you trust. No one will care for him as much as you do.
Be weary of people who are charming, outspoken. Just as much as they are genuinely enjoying spending time with your kid, they can easily be distracted.
I found this to be true for doctors too. The “good ones” don’t talk too much, they seem almost cold. They are interested in the facts and how they can help. Not in the weather and the latest gossips.
Kids usually check if you are watching them. But sometimes they get excited and start to do things that might be dangerous for them. Have your third eye opened and try to scan what they try to do. Don’t always help them either, but have a hand ready to step in if they get in trouble.
Some lessons you learn from books. Some lessons you learn from others. The best ones you learn from life and yourself.