The quality with which the forms are practiced has a major influence on the ability to apply the WT principles in actual combat.
The sequence of movements in the relatively short WingTsun forms is quickly learned, but even masters constantly refine their execution.
Naturally one could discuss countless aspects to which particular attention must be paid when practicing the forms, but the object of this series is not an exhaustive analysis of all the movements in a form. Instead Dai-Sifu Schembri provides examples of important aspects which should be noted.

Chum-Kiu

Part 1 – 2nd half:
After adopting the stance, the crossed Gan-Sao (Gau-Cha Gan-Sao) is performed. The arms are then brought to the crossed Tan-Sao position (Gau-Cha Tan-Sao) with an inner rotation (Kwan-Sao). The arms are then returned to their initial position (Sao-Kuen).
After performing a punch on each side, as in the 1st form, both hands are placed in front of the chest and thrust upwards as an explosive movement (Chuen-Kiu).
 

There is then a turn to the left while bending the arms, the left above the right. This is followed by a turn to the right, then back to the left.
Both arms are then stretched forward with the palms downward. The left forearm forming a Tan-Sao is struck with the right palm, then the right forearm with the left palm. This sequence is repeated twice more.
The right palm is thrust forward (Ching-Cheung) while the left hand adopts the Wu-Sao position. After performing this three times, there is a turn to the right while bending the arm to form Lan-Sao. A crossed Tan-Sao is then performed in front the chest, followed by a forward turn with Bong-Sao. This sequence is repeated twice more.
After the last Lan-Sao movement, a punch is executed over the right forearm with the right arm. The first section is concluded with a turn to the starting position and a Fak-Sao to the left. The whole sequence is repeated on the other side.

NOTE:
When returning from Bong-Wu/turn to Lan-Sao/Sao-Kuen, it is particularly important to ensure that all movements begin and end at the same time. Exactly at one point. The difficulty is that all the movements describe a different path. A very good coordination exercise.

Part 2:
 

The left hand is opened widely, the thumb extended away from the four fingers in the shape of a half-moon. The left hand is then pushed to the right while closing the hand to grab (Jor Kam-Lan). In its final opposition the hand is one hand’s length from the right shoulder. Now the left arm is pulled to the left, while the body weight is shifted onto the right leg. The left arm is now in the Lan-Sao position, with the left upper arm in line with the shoulders.
The left leg is then driven horizontally to the left with full power (Wang-Chang-Gerk). The upper body should not move during this kick. When the leg is fully extended, it is not retracted but set down to the front at full length. When the foot touches the ground, a forward step is executed with the body being drawn behind it under the “knee-pressure“ of the left leg. At the same time the arms perform Bong/Wu-Sao while the body is still turned. The position is held for a second, followed by a change to the crossed Tan-Sao (Gao-Cha Tan-Sao). This is repeated twice while moving to the left.
After the third Dap-Bo Bong-Sao (swinging arm with step) there is a turn to the left accompanied by a lifting punch. The body is then turned to the front, the right arm forms a Fook-Sao and the left arm performs Da-Ngan-Sao (eye-thrust) over it. The fist is withdrawn after a Huen-Sao movement.
The entire sequence is then repeated on the right.
NOTE: When performing the side-kick, it is important to ensure that the Lan-Sao does not move
When executing the lifting punch, it is important to ensure that the elbow is lowered with the fist striking upwards to the chin, without drawing back the arm first!
 

Part 3:
 

Turn to the left from IRAS (Juen-Ma), then perform a stamping kick to the front (Ching-San-Guek) with the left leg parallel to the ground and the heel thrust forward. The shoulders should not move during the kick.
Once the leg is fully extended it is set down vertically to the front. Draw your entire bodyweight  after it with the rear leg (Dap-Bo) while performing a double low Bong-

Sao (Dai-Bong-Sao). Change to a double Tan-Sao (Shang-Tan-Sao) after the step. Repeat the Bong-Tan-Sao sequence a total of three times and end with a low Bong-Sao.
After the third Dai-Bong-Sao, a short forward step is performed with the left leg. Then bring the right foot up next to the left and raise both arms to perform a double Man-Sao, with the backs of the hands touching and the fingers pointing upwards. This movement must take place at the same time as the feet come together.
Both arms are then jerked downwards to form a double shock hand (Shang-Jut-Sao), with the power coming from the elbows. Both palms are then thrust forward for a double vertical palm-strike (Shang-Tui-Cheung). When both arms are fully extended, drop the hands and perform an upward circular movement with them from inside to outside (Oi-Huen-Sao). The fists are then withdrawn (Sao-Kuen) and the right foot is placed behind the left foot (Dao-Dap-Bo). Then turn by 180° and repeat all the movements to the right.

REMEMBER: When moving to Tan-Sao from the double low Bong-Sao, make sure that you do not withdraw your elbows.
The change from the double low Bong-Sao to double Man-Sao must take place as the feet come together. All the movements end at the same moment.
Hint: Imagine that your arms are linked to your rear leg by a thread. When the arms are raised, the leg moves forward.

A detailed description of the Chum-Kiu form with numerous photos may be found in “Chum-Kiu of the WingTsun System“ by Grandmaster Leung Ting.
 

Source: WINGTSUN World