Thanks for contacting us! The most useful tools for this are the ‘Pro Adjust’ tool and the ‘Curves’ tool (which can both be found on the Pro tab). These Premium tools allow you to selectively adjust Exposure, Sharpness, Clarity and Color. By clicking the ‘Reverse Effect’ checkbox on the small ‘Effect Painting’ dialog which appears, you can apply the effect to only those areas that you paint on (as opposed to applying it to all areas except those you paint off).
Let us know if you have any further questions about these tools or anything else.