To get greater benefits when doing waist also known as obliques exercises rather than just repeating left, right, left, right, try varying the repetitions so left, right, left, left, right, right etc.
This reduces the momentum building up as you twist from side to side so your muscles have to work harder.
At our fitness and wellbeing retreat we ensure our guests exercise with good technique as is fundamental in your exercise, before reps or intensity. Without it exercises are less effective and can cause imbalances and injuries. Seek guidance from a personal trainer whether online or in person before doing new exercises and check your own technique in a mirror.