Using curves adjustments in Photoshop

[nsxr_]

Hi all, I've been using levels to adjust the contrast and brightness in my images and it has worked out well for me in uploading to JP. I have been wondering about curves adjustments and would like to know more about it and perhaps introduce it in my editing workflow. Would curves adjustments lead to overprocessing halos? What are the benefits of it over levels? How should I properly use curves adjustments? Any information or tips are greatly appreciated!

Thanks