If you're training for a distance race (5k or more) and not a sprint, then the best thing is to run a lot of kilometers. And the best way to do that without injury is to run slow. So it may sound strange but you learn to race fast by running slow, but running a lot.

Getting my leg presses up to 8 plates per side shot up my running speed without any running at all. So I would say focus on leg strength and practice running a lot and keep trying to improve your form using videos or something.

Have you heard of the 'Kettlebell Effect'? Its where your performance in other sports is noticeably enhanced because of kettlebell exercises, specifically Kettlebell Swings. They train your posterior chain and give you strength, stability and explosive power all around the hip region.

I do strength training in a gym with machines, barbells and dumbbells, but ive also started incorporating doublehanded kettlebell swings to my routine. 20 swings with a 20kg bell and im gasping for air!