[spectrrr]

For starters, Camera raw. much easier to get it semi right before it hits photoshop.

After that, the essential can't live without skill I think is LAYERS and MASKING. Being able to add a curves layer, then use a brush to paint in the effect where needed is invaluable.

ALWAYS work non-destructively - make a new layer for most new edits, that way you can always follow the breadcrumbs backwards to change something if its not working or needs tweaking.