===How to tell about your child's strength??

My four year old is amazing in creating her own songs. She likes to play pretend and with the songs she can go on and on.(it is funny to watch though:cb:)
But the thing is unlike my older one who is super smart and always picked up things taught in the first few tries, my younger one isnt as sharp.I can tell. She is reading words but wont proceed. I want to know what exactly her strength is , so that I can help her on focusing on it.I dont know how.Any suggestions on where to start?