Depending on your age/gender, 13.4 is a very quick time. Some basic things to improve are your reaction time to the gun, your mechanics of your start (how quickly can you get up to top speed), your form (running drills are your friends, learn to love them), and general conditioning (which means putting in some miles, not distance runner level, but still more than most sprinters would like to do).

depends on your gender and age.....!
i run a 13. flat. on my first year running track

same as zoe. i am 13 and i run a 12.5 or 6.

im 14.and i run mine at 12.1 i just started.but work on uper body strength to pull yu up and it helps.