I love freebies. Picking one up is liking buying something nice, only without the cost. For a limited time, you can download a free copy of Android Photography by Colby Brown. It's a simple primer for learning how to take photos using a, preferably stock, Android phone or tablet.
The basics, and I do mean basics, are covered here. The book opens with a description of the best way to hold a phone for both horizontal and vertical pictures, and while this may seem obvious to some users, there's no shame in admitting if your picture-taking form could use some work.
This book is written with the Nexus line of products in mind, and it's geared towards users running Android 4.2.2 or higher. If you have a Nexus 4 and are moving over from an HTC or Samsung product, this is a good way to get familiar with the latest version of the stock Android app. Brown provides pictures and goes through all of the app's options. Once you've taken your photo, there are sections dedicated to both sharing it and editing it using third-party applications such as Snapseed.
Android Photography is a pretty quick read, so have at it. Did I mention it's free?