You had good paneling for the most part and you have a little bit of a style going on.
Now, I'm not really of the opinion that manga has to read from right to left to be "authentic" but should read in whatever direction you or your nationality is use to reading so I'm glad you went with the decision to design it from left to right.
Some of the characters are drawn with very thin lines or details with thin lines that are also in different shades of grey. I think your manga would look better if all characters were drawn with just black lines with line weight at least equal to or similar to the background around them. Much like how you drew your protagonist in your chapter one when he's taking a shower. Leave whatever you want to do in gray to the gray tones anything that's a line just let it be black.
The only other suggestion I have is for the lettering. Your lettering isn't half bad it just needs some adjustments here and there. Usually when you letter you either want to do what's called anchor your lettering or pyramid it into a diamond shape. Now I only saw a few missed oppurtunities in your manga for the diamond shape. The rest just need to be anchored. Some of them are already somewhat anchored to the panel whether you knew that's what you were doing or not. Anchoring just means the text fits to the panel. Instead of a diamond think more like its half of a diamond shape and makes a pyramid and that pryamid is either right side up or uspide down depending on whether it's anchored to the top or bottom of the panel.
My manga had terrible lettering but I only found out after my first kickstarter so I went back and relettered so now I just launched a second Kickstarter for the same book Called Cold-Blooded Volume 1 Better letters make a better battle mangahttps://www.kickstarter.com/projects/perrys-hotter/cold-blooded-vol-1-better-letters-make-a-better-battle-manga?ref=user_menu Now, if you look at my manga on my account on here it still has the old lettering so I would not use that as reference but rather what not to do lol but I do intend to update it at some point on here with the new lettering at least up to my chapter 8.