Okay here goes:
The art looks like it is a good start. Though there is clearly much room for improvement. There are a few places where your anatomy gets a little wonky (Like the tall girl's leg/torso ratio is off here
) and there are places where some of your characters appear to be WAY taller than others, running the gamut from 3 feet to 10 feet tall. You clearly have a more cartoony style so you can get away with less accurate anatomy, but taking the time to study and practice some realistic anatomy would help.
Probably one of the biggest issues is that everyone (especially your female characters) seems to have the same dead expression on their face. The two elements of the face that tend to have the biggest influence on expression are the eyebrows and mouth. Even slight alterations in their shape and position can have a big influence on the characters perceived expression.
Here is a quick example I made using the exact same face each time, just altering the mouth and eyebrows.
You have very little variation in your characters eyebrows and almost none in their mouths. Making even small variations in their shape/placement can drastically alter the face's expression.
[Note: Above concept comes from Scott McCloud's Understanding Comics
It looks like you are working mostly in graphite and just scanning in the pages. This is making your art look kind of messy and a lot of the underlying sketches are still visible. If this is the sort of style you want for your comic that is fine. If you want to give your art a cleaner, more refined look though, there are a few ways to do so.
You could try inking your drawings and then erasing the pencil lines before you scan them.
Or, if you want to keep the graphite look, work on getting a bigger contrast between your darks and lights and clean up the smudges before scanning. (I don't know what program you use to finish your comic, but depending on what you use you may also be able to fool around with the levels of your drawings to make the darks darker and lights lighter and such.)
Cramped and hard to read. I would make your font maybe 2 points bigger and let the text breath a lot more in those bubbles. Also, they don't need such long pointers going directly to the characters mouth. Just a short pointer near the character is enough to get who is talking most of the time.