The solutions

Tip 1: Stand Tall

Stand evenly on two feet, keep your back straight, knees soft and buttocks squeezed. Imagine a string in the middle of your head pulling you tall. This should be your natural standing and walking posture.
Lengthening your spine and elongating your body will instantly add an inch or two to your height making you look longer and fitter, in addition to your clothes hanging better. This tip will reduce abdominal bulge and the possibility of low back-pain.

Tip 2: Don't Slouch - keep your back straight
Many of us slump with our shoulders rolled forward - especially if seated at a computer for long periods. Stand or sit up straight, push your shoulder blades together and down.
Increasing the width between your shoulders can make your waist look thinner and a broader chest can make men look more masculine. The chance of neck and shoulder pain is also reduced.

Tip 3: Tummy Tuck (without surgery)
Whilst standing tall or sitting up straight, pull in your tummy muscles all the way then release by half so you can still feel them working. Hold this position for as long as you can.
Repeating this exercise often can help tone your abdominal muscles and reduce the possibility of low back pain.

NB: Breathe normally whilst carrying out these tips.