Hi Christina,
I'm not 100% sure what you meant by words on the labels, but whether it's part of the illustration, or words that form part of the story, I reckon that a "handmade" type of font would probably help.
If you really needed the font to blend in with the illustration better, I would then consider giving the text layer a different blending mode. Another trick would be to not use 100% black as the colour, but try something maybe dark grey, dark brown?
Here's a little illustration of mine, which uses a handwriting style of font - is this the type of thing you mean?