How can i get faster??

i was a starter at the beginning of this year but i inflammed my achilles tendon so i was out 4 a week. then this guy came who is faster than me but i know all the routes and coverages and he dosent. the coach told me as soon as i get my speed back, ill be a starter again.im 13 yrs old,5-6, and im a wide receiver. any tips on how to get faster?thx!!!