I use curves often in my picture editing in Photoshop. A little tweak with curves can make a lot of different to the photo. Curves adjustment can be found from PS menu, image>adjustment>curves. To adjust contrast of my pictures, I never use the Brightness/contrast adjustment. It is just useless to me, I never use it since I found out how to use curves. If you don't know how to use the curves adjustment, sometimes it can lead you to spoiling the image rather than making it look better. Here bellow I put example of a simple tweak with curves which change the contrast and saturation of the images.
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I hope this useful for you all cheers!