This tutorial shows how to create starfields using a free plugin.
We start with a simple 2D starfield, but then use Fractal Noise to add atmospheric distortion (twinkling) and then I show how to save this effect as a preset, so it becomes really easy to reuse.
Next, I take a look at wrapping those 2D stars around the inside of a Sphere to create a 360 starfield. I use Video Copilot's free Orb plugin. Link to VC Orb: https://www.videocopilot.net/blog/?s=orb
Once it's all set up, I then show how to use an expression to switch between 2D and 360.
Finally, I create a 3D starfield you can fly through using CC Particle World, and another expression to make life much easier to control the amount of stars.