Parents should parent, which requires them to assess situations and, when needed, to step into their adult. We are all social animals and we learn through imitation. If you've ever watched your toddler imitate you while playing with dolls, trucks, or peers, you can see what an impact your behavior has on him. Be what you want to see.
You really are your child's first teacher. And from birth to death, all of the patterns your child learns interacting with you will inform his relationships forevermore. Remember when you said, "I'll never do to my child what my parents did to me"... and then you heard yourself repeating the same dialogue, as an echo from your past? That's how it works. Your child will take all of his cues from you. If you're calm, don't panic, and stay balanced in your interactions with your child, he will develop that same behavior.
Let your child tell you what he needs from you. This requires you to listen actively and have empathy for your child. Never discount his feelings when either his body or pride is hurt. Be his support -- his safe home team. If you're insecure, you will absolutely pass on your insecurities. Empower your child to honor his own feelings by being his reliable touchstone. If your child trusts you, he will trust himself and therefore, the outer world. And, relaxation techniques can help you stay in balance and not overreact emotionally to your child's experiences, whether an injury, a fight, or an illness.
Help your child realize that you are there for him, and you will support him to be there for himself. Thus, you are teaching your child to be independent by allowing him to feel bonded, safe, and secure. This will help him extend out and explore his world.
Nurturing is not smothering. Give your child the room to grow and to make mistakes. As a conscious parent, you can choose how to override your own fears, and therefore, build a strong and healthy child. If necessary, seek professional help for your insecurities, so that you don't pass them on.