RTFM. Your camera manual is there for a reason, for you to read it! One of the best ways to improve your photography is by knowing your equipment inside and out. Not knowing how to change your ISO or even worse leaving it on Auto ISO is terrible. You will always be fumbling with your camera which will prevent you from being a proficient photographer. My favorite app for iOS is Goodreader which allows me to save and search my camera manual from my iPhone anytime. Watch the video for more info.