Use a firm, deliberate tap
Tap the egg once on a flat work surface or a clean, firm rim. A flat surface tends to produce a broader fracture and is less likely to push a sharp shell edge inward. The goal is a clear central crack, not a crushed patch.
Open with your thumbs
Hold the crack upward over a small clean bowl. Press both thumbs into the fracture and pull the halves apart smoothly. Keep the opening close to the bowl so the yolk does not fall far enough to rupture.
Crack one egg at a time
For baking or a large batch, inspect each egg in a separate bowl before adding it to the others. This keeps a bad egg, blood spot or piece of shell from affecting the full mixture and makes shell fragments easier to remove.