Yes, you need to start with good documentation about your infrastructure and key applications. You need to know where the people you are serving are connecting from most often (Internet, local network, etc) and how you would like them to authenticate... and as you start pulling this information together you can start to see how building a hybrid cloud can help you put resources in the best place for your users or customers to access and how ease access issues with synchronized log-on credentials with Azure Active Directory.
To help with getting you started, my fellow friends and Evangelists pulled together 15 posts over the last few weeks to get you started, including 6 step-by-step guides!
I have two posts in the series:
For more general information about Azure, I have an Azure page where I list out links to information that's been hand to me. I really hope you find this stuff useful. There is a lot to learn, but a bunch of great ways to make it work for you.