You may already know this, and I'll apologize in advance if you do, but exposure is not the only way to brighten an image. My workflow is to first set the exposure slider to kiss the right. Then I adjust WB if required. Next up is to either do a slight increase or decrease on contrast as required. Now the highlights slider, which I generally pull down slightly. Hold down the alt/option key and adjust shadows. Hold down alt key and slide the white slider right til they just start to pop up. Do the same on the black slider to the left. If the histogram isn't showing a little red on the right raise the exposure slider just a tad till it does. Go to the tone curve and set a medium tone curve to start. Grab the top right point and move left or down while watching the histogram, you want to kiss the right and, depending on the image have a little red showing. Go to the left bottom corner and slide the point right or up while watching your histogram to set your black point. Now adjust your other points to taste.