Shimio
Sorry if the text is a little too small.
*squint* Yeah, it is a bit small.
This can be rectified by changing the sizes of boxes, bubbles, etc. where the text occurs. Plan the panels according to how much room the text will need. If the text takes up too much space, reconsider the size of the panel, or the amount of text in a single panel. It's also okay to do a comic in more than one page.
Legibility can also be improved by changing the font itself, which can affect both size and clarity of the letters (for instance, Comic Sans is easier to read than one of those scrawling cursive handwriting fonts, but Arial is more legible than Comic Sans).