Do a droplet shape

Something like this

Next put in the colors of the rainbow

And then blend them together until it looks "transparent"

Add the highlights on another layer

(Do not change the opacity just yet)

Put the background on another layer than you can change the highlight opacity to your liking

Remember to add a dark background

Use the air brush and make sure the color you use is same as the back ground

Make sure to do this on another layer

Do something like this

After that you can add more things to the background but other than that your done

So done ☆: .｡. o(≧▽≦)o .｡.:☆