It doesn't take much to acknowledge when someone does something right or put their best effort. Just as adults love to be complimented, so do children.  Have you ever heard the term "glows and grows?" When you see your child learn a new phonic sound, read that sentence with little to no errors, spell a word correctly that had been giving them trouble-give them a "glow", tell them how awesome they are, how impressed you are, and how they are growing as reader or writer. Giving them that "glow" will have them glowing. They will remember how they felt when they received that positive reinforcement.  Another way to give a glow is ask them to do it again. If they read a sentence with no errors, show how excited you are by wanting them to repeat it. If it is a writing assignment, have them read it aloud, almost like a performance.  Then you can show them their grows, weak areas, and let them know how excited you are when it turns into a glow. As long as they know you are proud and they are improving, they will continue to progress and gain more confidence every step of the way.