If you enjoy black and white processing, Silver Efex Pro 2 is a plug-in by Nik Software for Lightroom and Photoshop that you just can't live without. You can adjust brightness, contrast, structure and tones. Each section is broken down, so you can make specific adjustments to the whites, blacks and midtones in your image. There are many presets to try, as well as film types and borders to enhance your images. There's also point adjustments that work similar to an adjustment brush (only better) to touch up specific areas in a photo. Once you're happy with your image in Silver Efex, I prefer to transfer it over to Photoshop as a layer. You can, then, treat the layer as you ordinarily would; adjusting opacity, or adding a layer mask, etc.
So, here's my little willing muse with an Oreo facing the light coming in the sidelights of the front door of our house. I shot at ISO 400, f/1.6 at 1/320 with my 50mm. I spot metered off the left side of his face, which was the brightest side. I increased exposure by just under a stop to get the histogram I was after. I did add a film preset in Silver Efex and a bit of noise was added for even more of a film look.