Subway Job. How can i get faster?

i work at subway, ive been working about 2 months now. and im still told that i am slow. I'm afraid of getting fired. I go as fast as i can washing the dishes, sweeping and mopping floors, wiping tables, makking sandwiches, stocking foods, cleaning the bains, but im still slow at it. Should I get my coworker to time me? how can i do things as fast as possible, but still get it done correctly?