Hey @ahsaaan! I started with relatively high resolution JPEGs (RAW is better) with good compositions and good information/range captured in the image files. I just started using ACDSee instead of Photoshop. ACDSee is much more intuitive so I can more easily do more to the images. Besides overall color correction, I worked on the exposure of specific parts of some images.

Years of experience helps - I went to a tough technical photography school (Brooks Institute) during film days. One teacher used to say the most important tool you have is about eight inches behind the lens - your brain. Good luck with your photography!