I start with RAW first and shooting with your end product in mind will go a great way....nailing exposure....getting WB as close to proper as you can (I use Expodisk) go a great way to keeping your shot with at little editing as you can.

My philosophy is to use photoshop like bondo....not for filling huge gaping holes...but fine tuning a well massaged body and minor inperfections. That is how you avoid posturization.....the smaller your edits...the less chance of taking somthing over the edge.

Yes I flatten my image inbetween color spaces...doing so insures your edits continue on.

I find when I am doing things with my work...I zoom into areas most hit by the changes and insure they are not going too far. Color for color...and tonal range for shadow/mid/highlight. Then I back out and see what it looks like....and see if any areas are out of desired results.

I try to get the shot as close in the camera as I can...then mildly fine tune the end result.

Roman