Jiggle peeking and counter strafing are two of the most important skills in Valorant if you want to consistently win duels.
Jiggle peeking involves strafing in and out of corners to avoid taking excessive damage. It can even allow you to win disadvantageous fights if you have lower HP.
Counter strafing ties into jiggle peeking and it involves changing your strafing directions to make yourself harder to hit. You can counter strafe erratically to throw off your enemy's aim.
When you are counter strafing, you want to let go of one of your direction keys and tap the other way when doing a normal peek.
For smaller peeks, you don't need to tap in the other direction for too long.
You want to let go of one direction key and HOLD the opposite key if you want to jiggle peek and still shoot accurately.
You DO NOT want to hold both your A and D (left and right) keys as it delays your strafes making you easier to get hit.