This is Slasher's "Road to Top 200", focusing on Windranger. However, the tips he gives are applicable to many engagements.
Positioning and Zone Control, by FiercE:
I like this video more because it talks about some very basic things, that new players don't even think about. I find the information he shares to be most valuable to support players who are wondering what to do in team fights, and how to stay alive when low on farm.
Teamfight Analysis of Positioning:
A very chaotic teamfight between Na'Vi and C9, broken down to enable you to see why each player on Na'Vi is doing what they are doing.