Laptop battery life best practices?

Till now, I have always had laptops where I could remove the battery completely. Every time I know I am going to be using my laptop as a "desktop replacement", when I know my laptop is going to stay stationary at my desk for long periods of time, I have always removed the battery and had my charger plugged in.

I just got a Precision 5510, and it has an internal battery. How do I maximize the life of it? I keep it at a desk most of the time, and occasionally use it on the flight, at airports etc where I truly use it as a laptop. Is it ok to keep it plugged in and at 100% all the time? Should I keep cycling it between 80% and 20% constantly? 

Anyone have any recommendations for how I should be handling the battery? I am basically worried about it losing its capacity as a result of a higher temperature from constantly keeping it charged and at 100%.