(I added a redline btw^^ Just in case^^)
If you cannot read my writing then:
1.To do shading you should use the tool 'burn'. Set it's opacity to 0%, same with it's colour.
Shade wherever you want it, and if it's not light enough, go over it one more time.
2.You should also use dodge. Do exactly the same that you did with burn, but this is better to use. It will look good with both.
(Good advice to use this first, but wither way, it doesn't matter^^)
Hope these help!