I think you need to plan your speech bubbles more. Some of them look a bit cramped.
Firstly you should probably do rough thumbnails of your page layout (if you aren't already) accounting for your speech bubbles in your layout (otherwise you might find you've drawn art you're really attached to, but can't fit the speech bubble in anywhere)
when you come to draw your comic, you might find it helpful if you write the text in first and then draw the speech bubble around it. That way you won't have to squish up your writing to fit it all in.
Firstly you should probably do rough thumbnails of your page layout (if you aren't already) accounting for your speech bubbles in your layout (otherwise you might find you've drawn art you're really attached to, but can't fit the speech bubble in anywhere)
when you come to draw your comic, you might find it helpful if you write the text in first and then draw the speech bubble around it. That way you won't have to squish up your writing to fit it all in.