Before you start casting, learn how to choose the right fly line based on the type of fish that you're targeting.The roll casting technique is used when there's no room behind you to cast. It can be practiced on the water.
The roll casting technique is very effective and efficient when used on streams or creeks. It allows you to cast whenever a backcasting isn't possible. It can also be used when there's a stiff wind at your back, and you need to quickly reset your fly.

Follow these four steps to get started on practicing how to cast in tight spots:

1.Make sure that there aren't any tangles in your fly line as you hold the rod in front of you.
2.Turn the tip back so that a small section of line hangs loosely behind you.
3.As you move the fly rod, slowly increase the speed and gradually decrease the distance.
4.Then, stop when the tip of the rod is pointing slightly upward. Watch the loop unfold as it starts to move.

Although the roll casting technique is mainly focused on the type of fish that you're targeting, it can also be used with the right fly line. For instance, if you're planning on fishing for fish that come to the surface, you should choose the floating line. On the other hand, if you're planning on fishing for underwater targets, you should use the sinking line.

SAFETY TIPS
1.When casting a roll, make sure that you're wearing sunglasses so that the hook doesn't accidentally snag your eye. These will reduce the glare on the water and allow you to see the fish.
2.When you're out fishing with a buddy, make sure that you're wearing a life jacket. Also, avoid moving water. In addition, always stay away from dams.

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