To help me answer your question, I turned to a good friend who works at a leading provider of child day care and education (don't want to name names). While her Masters degree in education and extensive experience makes her a great teacher, it's her personal style—both on and off the job—that makes her truly qualified to respond to this question! Here's what she had to say:
Mix affordable pieces from Old Navy with comfy flats for a cute, kid-friendly look that's professional, too.
Flutter Sleeve Top, $10; Cardigan, $20; Khakis, $15; Belt, $12.50; Crocs Prima Ballet Flats, $17.95; Earrings, $5
"Dresses and skirts are hard to wear because they are impractical for kneeling and sitting on the ground (I also know a teacher who had a bad experience with a curious child). Khaki pants or dark wash jeans are great because they are comfortable, but still can look professional/put together. Any shirt is fine, unless it has something dangly for the kids to pull on or is low-cut. Old Navy and Target have a lot of pretty shirts made from t-shirt material that can still look professional. Fun ballet flats are a great way to be comfortable and stylish while still being in compliance with most dress codes. They even make Croc ballet flats."
Regarding the Crocs, my friend also mentioned that waterproof shoes are a godsend when dealing with tots (just rinse clean when the inevitable mess happens!).
Calling all teachers: How do YOU stay stylish on the job (especially if you're dealing with small children)?