Reducing noise in Adobe Camera Raw and Lightroom (the controls and results are identical) is easy. There are only two sliders for two different kinds of noise—Luminance and Color. Zoom into an image at 100% magnification and move the sliders until noise is reduced, but image quality isn’t compromised. Use restraint. In a majority of situations, it’s better to preserve a little noise than to blur the image substantially.
All noise reduction blurs images. Sharpening after noise reduction during RAW conversion is recommended. Knowing that you’ll sharpen an image after noise reduction, you may reduce noise more aggressively initially.
There are limits to how far you’ll want to go. Noise can be so aggressively reduced that surfaces within images become textureless and begin to seem synthetically rendered with software rather than optically captured photographically. This effect may become more pronounced if contours are strongly exaggerated during sharpening. While sharpening, take care not to accentuate noise further. Develop a sensitivity for texture and contour, and use your best judgment. You know what things look like. Make your images look convincing to you, and you’ll quickly convince others.