How to cover your feet inside the circle? Improve you tackling skills

Analysing the play we can see that several body mistakes were made:

1. Very upright position of the body inside the circle.
2. Left hand very high and vertical
3. Feet on the same line planted on the ground.
4. No sidesteps to play the 1v1 instead the player was still running.
5. Not slowing down the speed and keeping the correct distance.