How to become a better runner? Start and Finish at the Same Place

I have been a runner consistently since 2012.  It is certainly not a long time, and I feel that despite the plethora of available information today about running, I have gained all of my experience by mostly trial and error. Through failure and progress, I sense that I have moved forward in a short amount of time.  Case in point, I feel that my finishing times have stagnated over the last year.  I have tried long runs to build stamina, and short interval runs to become faster, yet both of these ordeals have either driven me to run  too slow or to become too tired too fast.  However, I have finally discovered something that has helped me improve my running speed and endurance.  Over the past three or four weeks, I have been doing mostly timed tempo runs that demand me to start and finish at the same place—no I don’t walk the first half and jog the second half to finish early!  Seriously, depending on the duration of the run, I go between 15-25 minutes one way  and then turn back and hope to finish where I started in the same amount of time.  Usually, I finish about 10 seconds late; however, yesterday I did a longer run for 50 minutes and I strangely finished almost a minute sooner, and I was not ever that tired to boot!  Moreover, I went out today in the summer heat and did 20k at a moderate marathon pace (around 5:00/km for me) and all things considered I was not really that tired.   

So dear reader, if you are reading this I whole heatedly suggest trying these runs. They are painful at first.  And in the beginning, you will wheeze; you will shuffle your feet; you will curse.  In the end though, it will  really pay off in dividends.  I will be doing these tempo runs for the next three weeks, with the exception of a  long slower run on Sundays to build up my marathon stamina.  As a result of this, I am hoping to finish with a PB at the Warsaw Praski Half Marathon at the end of the month.  I am optimistic and hoping for the best.