keep going with this you developing your skills really good. keep up the work man! the only thing that that i see that needs improvement is your line work within the letters. if you notice in almost all of your work the lines in the letters are very shaky and sloppy, idk if you do your whole pieces in 1 session. If so try breaking it up into 2 sessions so that you will be refreshed, because it looks like you get to the end and you just want it to be done so you are trying to hurry but your going slow to stay steady and it will make you shaky. that is something that i have learned. or you can slow down or speed up, as you may probably know from painting there is 2 ways 2 get a nice crispy line.
slow = control , speed = nice smooth lines
but you have to learn how control both methods, it takes alot of time to master this.