DEN is a MASSIVE airport, but it is quite easy to make connections at, especially if your two connecting flights are on the same airline. There are 3 long concourses, A, B and C, and they are connected to each other by a tram system. The map would look a little like this: |-|-| where the vertical lines are the concourses, and the short horizontal lines are the tramways.
My experience has been that if you are flying a United-branded flight, they all arrive and depart from one concourse. Making your connection is simply a matter of hopping on the people movers and making your way down the length of the terminal Very simple, and I've always made my connections this way - even the tight ones.
If you are flying a Ted-branded flight and connecting to a United flight, or if you are flying two different airlines, you will likely arrive at one concourse and take the tram to another for your 2nd flight. This is extremely easy to do, though. Very fast.
You can check the DEN airport website for arrivals/departures to see what concourse and gates your flight numbers generally use (they seem to be quite consistent, i.e. the 8am from YVR alwasy arrives at B50-something). If you find that you will have to change concourses to make your connection, call the airline and ask to be moved to seats near the front of the plane so you can get off quickly.
Hope that helps!
