My boss said im slow at work?

so i just now recieved a job a papa Murphy's answering the phones,making pizzas etcetera well while i was making a pizza for a customer my boss tapped me and said i was too slow :( not only for making pizza's but also lectured me telling me while i was wrapping the pizza up " that is the worst wrapping i have ever seen in all my years working here" it really is getting me down my boss always picking on me any tips for speeding up? i think i really annoy my boss and well today was my first day