How to sing a scale without having your voice crack

Intro

Are you tired of having to stop singing because your voice keeps breaking? This will help you.

Before you sing, drink some water. If you are going to a concert then hold a teaspoon of olive oil in your mouth. Swish it around your throat to make your throat relaxed.
Don't over-practise. Practising to much can damage your vocal chords. If you are preparing to perform, you don't want a sore throat!
Hum. Hum the scale so you know what you want it to sound like.
Sing! Start out soft, and work your way up.