I am not so sure, whether you can get much helpful critique here. I mean, from what I see, you know the techniques. Doesn't mean you already mastered them (whatever heighty goal that may describe), but you know them already, you heard of em, and you at least tried them out and put in the hours to practice them. Nitpicking your drawings and telling you out on every slip-up won't teach you much valuable things, because frankly, there aren't many slip-ups anyway, and they hurt your eyes probably more than mine.
I love the effect of black and white chalks on a grey background for sure, maybe this will inspire my next art supply run.
Maybe the next step for you should be to stop worrying about technique and start thinking about audience. Who do you want to draw for, what could catch their eyes and their imagination? Try out a social media site maybe, DeviantArt, Artstation, Instagram? post your stuff there and keep an eye on which of your drawings get the most reactions and the most likes?
Or dig out those memories of those images you wanted to draw, before you started to practice so hard?
Or maybe giving critiques to other artists may be more informative for you, than receiving critique at this stage, unless you find someone who can really make your jaw drop.