I'm not an expert neither, but sprinting and tackling are basically the only two things i do really well.

to run faster, i begin running giving many "short steps" in a fast way in order to accelerate more quickly...and once i have already accelerated, i give larger steps to sprint faster.

it's difficult to explain, i hope you understand.

but yeah, it's a great advice to train short runs, instead of long distances. good luck