A good deep breath begins from the diaphragm and streams towards the upper part of the lungs. During outhale push the air out beginning from the lower of part of your lungs. An effective breathing technic can be practiced for example by playing long notes with concentrated observation. Effective inhaling can be learned in time by playing e.g. exercises and tunes. At first you can try how long you can play a tune until you must breath in. Smooth places to breath when playing a tune could be phrase ends. Of course the player has right to breath anywhere she or he wants.
Controlling the air stream is the most effective when your lungs are never completely full or empty. You can try to always keep your lungs minimum 1/5 full and 1/5 empty.