What are productive ways to increase running speed.

I think that you should just run a few hours every day just going a few many miles one way and run back to your house.

As you're running, sprint for a few seconds/minutes then back to normal speed. Do this periodically through your routine and add more sprints as time goes on. Space it out, don't try and do it all at once.

Find a gentle hill. Sprint down that hill every day for a few weeks. Find a steeper hill and then sprint down that hill every day for a few weeks. Another way is to practice running with the wind. Sprint with the wind pushing you, then walk back and start again. You might find that light weights may also help. Adding little by little can help increase your speed, especially if you do as I have said before, running downhill and with the wind. These drills help increase leg mobility, enabling your legs to move faster and therefore, run faster.