Step 1: Hold Down
Make sure that the acrylic is held down securely. If it's not it can vibrate or flex ruining your cut altogether or marring the finish. On a T-Slot tabletop,with a sacrificial board, a few strips of double sided tape on the back side will go a long way to secure the piece. If you prefer, you can also use spray adhesives. Just make sure that the chemical properties are suitable for acrylic. A Vacuum Hold Table can make things easier, but if you're cutting pieces with a small surface area you may want to take these precautions as well.