So I made a list of 2-pages worth of praise and encouragement words that we commonly use in English and found the Spanish translations for them.
Here's a sampling:
¡Buen trabajo! Good job! Good work!
¡Bien hecho! Well done!
¡Lo hiciste! You did it!
¡Eso es! That’s it!¡Puedes hacerlo! You can do it!
Have fun encouraging your child in Spanish and let me know how the list is going for you.