We all have those days, wherein we hardly even put on makeup..we didn't even know the difference between direct flash and having ambient light (Although that technical aspect of lighting isn't really something you need to know it helps in terms of ambiance)
Not perfect: But aiming for it
We all improve gradually
Not at the same rate, but we all do... just keep that in mind and stop looking at other people and comparing yourself. There are a lot of differences between people. (Circumstances/ resources like money and time) they all differ. And it would only cause you a load of stress and maybe even a bit of sadness if you do.
So just take it at a stride!
Study whenever you can regarding the components you see yourself as lacking. Save for that "One big photo shoot",or that "one big costume project" that am sure will be worth all the time. If you're not seeing any improvements in your final output? Maybe try re-thinking whatever your into, in this case cosplay. If you aren't really interested in seeing better results or going over your own limits...don't expect better results.