One thing that has really pushed my photo editing and manipulation game to the next level is my ability to select exactly what I want and need.
Those little "marching ants" is what is keep you back from some exemplary work. Even with the best typographical, composition, color theory and illustration skills. If you are making crap selections for your photography then it will painfully show through.
A lot of young designers do not put enough practice into selections simply because it is hard and tedious. Do not get me wrong, it sure can be. Understanding photo resolution, how the selection lines interact with the pixels, how to adjust your feathering, which tools are used to create the best selections needs etc. It can be pretty daunting for a newbie, let alone someone who has been at it for awhile. But with many hours of practice it is well worth the pay off.
The basic selection tools are a great way to get started. Practicing with how everything interacts with one another will help you build a quality foundation. Just getting good at those is an accomplishment.
If you want to step up your game you can learn how to use layer masks. I used masks for awhile but I found it bothersome and lacking the exactitude that I wanted and needed. At least for my liking. So i ditched that for the tried and true pen tool.
Being able to control exactly where the pen line goes has helped me create perfect selections for any type of editing need.
I cannot stress taking the time to learn the pen tool, how to use the anchors and get your ants marching just right.
But maybe you like the other tools better, maybe you have a way that is different then my own. That is wonderful. Whatever you find yourself enjoying the most is the best tool for the job.
Make amazing selections and do some beautiful edits.