>>5310270short explanation of how i do this,
1 crop at desired ratio, expand to keep everything i want.
2 content aware fill of the blank area, hope it looks nice
3 if content aware doesn't look nice
a. clone stamp out small stuff
b. start taking selections of good area and making layers and moving them around to the areas that are bad.
c. rebuild and parts of the focus or background that were not added with stamp and brushes.
4 check work
5 fix big mistakes
6 fix little mistakes (optional)