Try this. After your normal warm up and drills, run
3 sets of 3x200m with 60 seconds between each rep and a lap slow jog between sets.
Run the first 200m of each set normally for 130m, then over the last 70m, swing your arms faster, chop your stride a little shorter, and speed your cadence up a lot.
For the second 200m, run normally for 130m, then over the last 70m, push off forcefully with each step. Cadence can slow down a little. The purpose of this drill is NOT to go faster yet. It is to increase stride length.
For the 3rd 200m, run normally for 130m, then over the last 70m, increase your cadence by swinging your arms faster AND pushing off harder. This time you will speed up... a lot. You will be tired, but don't worry. After the 3rd rep, you get a one lap jog recovery before doing the second set. Your form will break down a bit. Try to maintain good form as best you can, but don't worry about it. Your form at speed will increase with practice.
If you need a little more rest than 60 seconds, take more rest.
The next week, repeat this workout, but increase the drill part of the distance from 70m to 80m. You want to build up to 100m and then to 150m.