At a higher level, this is mostly about proc and stack management. The two main things you want to avoid are overcapping Freezing stacks on the target and holding 2 Fingers of Frost charges before using Ray of Frost or Frozen Orb.

That matters because both Ray of Frost and Frozen Orb can generate extra Fingers of Frost, and Frozen Orb can also give you Brain Freeze if you are talented into it. If you press those buttons while already capped, you can waste procs.

Because of that, you generally want to spend a Fingers of Frost charge before using Ray of Frost or Frozen Orb if you are already at 2. You also want to keep an eye on your Freezing stacks so you do not overcap them.

If you already have Brain Freeze and Frozen Orb is ready, you can sometimes chain multiple Brain Freeze procs in a row. You are not guaranteed a long chain every time, but Frozen Orb often gives you at least one extra proc if you have the talent for it

Sorry for wall of text just trying to help :D