If your piping tip is too perpendicular to the cake, your shells make look too spherical and bulbous. If the angle is too acute, your ruffles may fall flat.

The small round tips are especially good for piping out macaron shells. Small star (Wilton or Ateco 32): For shell borders, smaller stars, or dainty rosettes, reach for this tip.

To form even shells, hold the piping bag directly above where you want your cookie and use even pressure to fill each circle; "stop, cut, and turn" the piping bag to give your cookie a smooth surface.