Before you start using this casting technique, make sure that you thoroughly understand it. It will serve as the basis for all other fly casting techniques.

This technique is commonly used when there are plenty of open areas behind you and you need to move your fly further out into the water. 
One of the most common and basic fly casting techniques is the two stroke technique, which consists of a forward and a back cast. It’s very easy to practice this technique on land, as long as you have an open spot. To start, tie a small piece of bright yarn around the tippet and watch it unfurl.

Follow these steps for four steps to learn how to perform this simple technique.
1.Take out three rod-lengths of line. With your dominant hand, hold the rod in front of you and make sure that there are no tangles.
2.The rod tip should be brought back in a steady and swift movement.
3.As the tip is pointing up and behind you, watch as you back cast until the line begins to unfurl.
4.Before the line completely straightens out, bring the rod back to the front.

TWO STROKE CASTING: BEWARE OF BAD LOOPS

Article refer:
1.Basic Fly Casting Techniques -Two Stroke Casting
2.Various Types of Fly Fishing Haul Casting Techniques
3.Some Roll Casting Technique For Beginner
4 tips for beginner musky anglers
5.Favorite Fly Patterns for Lakes
6.Can You Fly Fish in Windy Conditions? (7 Tips to Cast in Wind)
7.What equipment is needed for fly fishing for sockeye salmon?
8.How to prepare fly fishing gear for striped bass？
9.The Five Stages of Fly Fishing
10.Flying gear: six fishermen necessities