Get on your hands and feet in front of a wall, with your feet against the wall.
Walk your feet up the wall, while walking your hands closer to the wall.
If you have already practice the Incline wall handstand and are comfortable at an angle, progressively get your hands closer to the wall, until you can eventually place them right by the wall.
Bring your legs together and straighten your body. Hold that position for time and aim to improve your form as you practice it.
Keep enough strength to exit the handstand safely, by walking your hands forward, or letting your legs drop to the side.
Form tips
The hands should be about shoulder-width apart, so that the arms are vertically placed under the shoulders.
The arms should be straight at the elbows.
Aim to open at the shoulders, so that your arms are aligned with your torso.
Aim to straighten your lower back as well, by using a posterior Pelvic tilt and pulling your bellybutton towards your spine.