A friend of mine recently published a book for parents titled 'Teaching Speech the Fun Way". It's basically a 'how-to' book for parents to teach their children proper articulation techniques. If your child struggles with just a few sounds/has just a few sound errors- I'd highly recommend this book!
Right now, it's only $10 on Amazon and qualifies for free shipping! Monica in no way asked me to write this post- I've just recommended it to so many of my clients, I figure why not put it out there on my blog too! :)