Although his books is focused to parents, and not teachers, I think his ABCs of Self Esteem certainly can apply to our classrooms.
A is for Acceptance: Children need to feel that they are accepted for who they are. Now I have to confess, it's easier with some children than others. But the children who we find it most difficult to accept are the ones who are crying out for acceptance the most. I can tell you that I have prayed specifically for Heavenly Father to help me accept and love certain children and he has always answered my prayers. If I remember to look into the child eyes I see them as Children of God and I can accept them, faults and all.
B is for Belonging: Individual children need to feel that the group is somehow incomplete when they are not there. They belong in your class. They are part of the class. And when they are gone we miss something. Make sure to mention children when they are not in class, especially inactive children. Tell the children you miss them when they return. Pray that you can appreciate what each child brings to the group.
C is for Competence: Yes, this one surprised me too, but it really shouldn't. When we feel like we are good at something it makes us feel good about ourselves, even adults. Find ways to point out positive things that the children in your class are good at. If she is good at reading, be sure to have her read in class. If he is good at artwork, ask him to draw something for your next lesson. Or if she is especially kind towards others be sure to point it out and let her know she has a talent. Talk to them and find out if they pursue a certain sport or hobby that they are enjoy--chances are if they enjoy it, its because they feel like they are good at it.
Even though Dr. Leman doesn't mention it, I think the most import thing we can do to build children's self esteem is to teach them who they are--Children of God. Let's remember every week to teach our children who they are with our actions, words, and love. If they can feel good about themselves while they are in Primary they will always want to return--and that will make it a better place for all of us.