Another good place is on 'Inferno' if you start a bhop down 'Banana' from 'Car' you will be able to get a lot of speed mainly because it's downhill. Look for a flat surface an example is on 'Nuke.' Yard is an excellent place to bhop because the floor is so flat and easier to gain speed. Even people who have been trying to bhop for hundreds of hours still don't have it perfectly and you probably never will bhop perfectly mainly because of the surfaces on the ground. Learning to strafe and bhop is possibly the hardest thing you can learn because it takes practice and many hours to get it down. If it wasn't for his speed he wouldn't have been able to get that frag because they didn't expect him to get there so fast.
As you can see from the clip, he got up to 'Short' on Dust II and then proceeded down onto 'Cat.' As he hit the stairs he managed to start a sideways bhop gaining speed faster than walking normally and gets a frag onto a player on T spawn.