The most effective process is applicable to any Lithium Ion battery, which is different than other types of batteries.
Keeping these batteries plugged in and charged at 100% is detrimental to battery life. I've read that full charge, discharge cycles aren't ideal either. It seems the best approach is to vary it a bit, get down to 20% or lower and then recharge. Once it's charged pull the plug. Keep the battery cool also helps, which is pretty difficult to control, beyond not having it sitting in direct sunlight or in a hot car.
But it's all relative, there's no reason to be obsessive. Most people end up replacing their phones well before battery life is an obvious problem. I had my last phone for 2 years and over the last 6 months I was noticing decreased battery life. Even sitting around I had to put it on the charger every evening. Although, oddly, now I have it permanently in airplane mode and it goes for weeks before needed to be recharged. So there are a lot of factors in play here.
I'm sure there are people who can provide better information about this than I.