I'm having trouble developing ranges for 3betting preflop. I understand conceptually a great deal of what is discussed in Peter Clarke's book, for instance. But when it comes to in game play, I often don't have a feel for where the bottom of my range should really be. I get the sense that I cold-call too much and could be 3- (and 4-betting) a lot more for value.

On the learning path or in the library, are there videos you'd recommend?