Since this word is made up of a single kanji, it should use the kun'yomi reading. When learning the kanji, you didn't learn that reading, so here's a mnemonic to help you with this word:
In the sky, you are the ruler. You are known as "The soarer!" (そら). Imagine your theme song and make sure it includes "soarer of the sky" or something awesome like that.
There is a beautiful rainbow in the sky.
They say that women's minds and the autumn skies change quickly, but men's minds change quickly too.
I hope the sky tonight is clear enough for us to see the famous scene from the movie E.T.