-Quality is really low.
-Colors of the pentooling, are really unfitting to the stock
-the stock itself is horrible quality
-The whole thing is overexposed
-At least if you are pentooling, try to keep a nice flow to it, rather than having horizontals and Verticals.
If you are practising Pentooling for the first time, dont even touch stocks. Just simply create a new image, and fill it black, then add a nice radial gradient from light gray to black on it, then start doing subtle pentooling.