First of all, where do you live in Hawaii? Depending on where, you might want to attribute your struggles to weather.
Let me preface this with the fact that I've been running 6 years, and I've been alright.
Diets, training, sleep and stress are all highly connected to success or lack of it.
Balanced meals and 8+ hours of sleep are a barrier preventing most people from reaching peak performance.
As for training, it's important to cross train (bike or swim) at least 1 day a week.
It's important to find your "aerobic threshold" or the pace at which you can sustain while not breathing too hard.
Staying below that for your recovery and long runs is an easy way to avoid overtraining.
I could talk about this stuff for hours so add me my man