The recommended procedure is to start from the top and work down. That means starting with Exposure, but LR4 Exposure is very different from LR3 Exposure. It is more like Brightness. Instead of starting by setting your white point, you start by using Exposure to set your midtones. Forget about white and black points for now. Next adjust Contrast which is more important than it was in LR3 because the default rendering is flatter. Next Highlights; if you have ETTRed and set negative Exposure to compensate, it has some highlight recovery built in and you tweak it with Highlight which is better than the old Recovery because it doesn't have the flattening effect. Taking it to the left you can bring out huge detail. Shadows you use pretty much like Fill Light but it doesn't pull up the black point the way Fill did. Finally you finish by setting the Whites and Black sliders, if it is needed. It is a workflow that is probably more intuitive for new users, but can be a **** to reset your mind to if you're used to LR3.
A word about Clarity: It is now much stronger and with less danger of haloes, so it is easy to overdo. Also, because it is essentially just midtone contrast increase, after setting it you may want to go back and tweak Contrast.