Without seeing a sample image, it’s hard to advise you on which approach to take, but here’s a starting point. Press Ctrl-L to add a Levels adjustment. The histogram in the center appears to be a black blob, but is a bunch of vertical lines packed tightly together. Those toward the left represent the shadow details, and the ones toward the right are for the highlights. From your description, I’d guess your histogram will be biased toward the left, indicating a lack of highlights.
Grab the white triangle just below the histogram and drag it leftward until the contrast improves and the highlights look better. If histogram bars are missing or very weak on the left side, drag the black triangle rightward to deepen shadows and add more contrast. If the overall image now appears too dark or light, drag the gray triangle to achieve the best look.
You can do exactly the same thing (and more) with a Curves adjustment, but you may find the Levels dialog more intuitive at this point. With either Levels or Curves, try clicking the Auto button. Tinker with the Options as well. Sometimes that works beautifully, sometimes not.
If you have a problem getting the look you want, post an image at www.pixentral.com. Come back here and post a link to it so someone can give you more tailored advice.
