I hope my article helps you 
Children love rewards so it is an awesome idea to be applied 
There are 4 skills 
Reading 
Writing 
listening 
Speaking (is) the most important 
I suggest that you can enrich your mind and improve all of 4 skills by 
1- Watching videos on You Tube then write the new expressions or vocabulary that said and repeat them with a loud voice 
2- Reading books about language as those which speak about prepositions /phrasal verbs /expressions etc 
3- Flash cards /pictures are so wonderful and effective