Clearing turns are very important
If you are getting your license, you probably have experienced your instructor being very adamant you do these clearing turns consistently and correctly. It is mandatory you understand them for your flight test: if you show the examiner a lax attitude when checking for traffic, that is not only dangerous, but will constitute a fail.
So what is the proper way to do clearing turns, and why do we need to do them?
The real reason is safety.
When we do any maneuver practicing upper air work, be it slow flight, steep turns, stalls, spins, spirals, or whatever, we always do clearing turns. We check for traffic by turning 90 degrees in each direction, using a consistent angle of bank (my instructor likes 30 degrees). Then you roll around back to your original intended heading (you hope!) knowing that you have had a good look primarily behind you. There is no real guide or standard as to how to exactly perform the clearance turns, but as long as something is done to actively check for traffic using turns.
To start always look to the right or left first, whichever way you intend to turn and verbalize that you are doing this. Strain your neck, really have a good look, and say “clear for traffic on the left”. Do your turn. Then do this for the right side. Look, bend your neck to have a good look, and say “clear for traffic on the right”. When you have completed the turn have a look around.
Generally, it is better to start from the left rather than from the right. Overtaking aircraft are to pass on the right side; so if you take a right turn you may inadvertently cut an airplane off trying to pass you on the right. But regardless which direction you start from, make sure you have a good look around before changing your heading.
I used to think these turns didn’t accomplish much and was skeptical about how effective they are. I thought they left a section of sky unobserved. But think about it, you can see to the right or left without turning, and when you turn in either direction you can see behind you. You can imagine it’s like doing a shoulder check.