I'm not a big crier but occasionally I'll cry when cutting an onion. I've tried the "bread-under-my-lip" trick and it didn't work for me. Actually I just ended up eating the bread. So here are some tricks I've found that help.
1. Use sweet onions.
2. Peel & cut onions under running water.
3. If you have a gas stove, chop near an open flame.
4. My favorite! Refrigerate your onion(s) for at least 4 hours before cutting. Occasionally, I've even frozen them, although they're harder to cut.