A bit of disclaimer: I have taken a PT course with National Academy of Sports Medicine (NASM) and had been an athlete for as long as I can remember.

Although results will vary for different people, this is what worked for my girlfriend.

First, understand what causes anterior pelvic tilt.

Anterior pelvic tilt is caused by the shortening of the hip flexors, and the lengthening of the hip extensors. This leads to an increased curvature of the lower spine, and of the upper back.

Next, diagnose whether the condition really is an anterior pelvic tilt. Anterior pelvic tilt is characterised by a forward tipped pelvis that causes the hips to push out back and the abdominals to stick out forward.

Once confirmed, take note of the other conditions the person has to make a more holistic recommendation. For my girlfriend, I know that she has really tight hamstrings and constant lower back pain.

With these knowledge, I advised her to stick to the following exercise regimen for a period of 3 months.

Exercise 1: Kneeling Hip Flexor Stretch

Gradually extend the hind leg and lower the body to fully stretch out the hip flexors
3 sets x 2mins
Progressive overload as conditions improve and as the exercise gets easier

Exercise 2: Glute Bridge

Done with perfect form and no excessive arching of the lower back
3 sets x 20 reps

Exercise 3: Cat-Cow Stretch

Controlled 2 second cat and 2 second cow stretch
3 sets x 15 reps

With these 3 daily exercises, I was able to get my girlfriend to gradually fix her anterior pelvic tilt to the point of not having any back pains anymore and a significant postural improvement without her glutes sticking out.

It's a significant improvement in her quality of life and she's extremely happy because of it.