This was an attempt to show a workflow on a single image. Whether or not it flows or works remains to be seen.... :D
Anyhoo, this vid contains an in depth look at the plugin gradient Xterminator - do's and don'ts.
Some basic levels and curves, and rescuing star colour.
Note: I tried to incorporate a mistake into the tutorial, showing what happens if gradient x terminator isn't used correctly - so watch it until the end for proper use of the plug in. 😉