While your tween is beginning to develop their own identity and worldview, you'd need to balance parental guidance with giving them room to test their wings in the controlled and safe environment of home.
Prepare your child well in advance for what puberty will bring: the changes in their bodies, emotional ups and downs, the importance of friends and peer pressure, greater independence and heavier responsibilites. The multiple changes can be overwhelming so assure them that your love and God's love for them are constant.
As pre-teens go through puberty, they experience many physical, hormonal and social changes, making them prone to wide mood swings and strong emotional responses during this turbulent period. Assure them that you went through puberty too (not too long ago), and that this too shall pass.