If you've gone down the grayscale route, you may want to split-tone your image. This is similar to the old method of mixing, for example a sepia tone with a platinum tone in the old chemical darkroom, except with a lot more control. You can select the tones for highlight and shadow areas, then use the saturation to find the right density of colour and the balance tool to mix the dominance of the two tones.
Once this is done, using the workflow method of moving from panel to panel, the Detail section, including sharpening and noise reduction can be used.
Noise reduction includes luminance and colour noise, but be careful with these two, as the image can lose sharpness and look soft. The Sharpening tool is very clever though, with a neat trick of letting you control the edges to be sharpened using a controllable mask. By pressing down the Alt key as you move the sliders you can see the effect of the sliders on the image. The Detail slider lets you see the sharpness applied to the edges, by using an embossed mask, while the Alt/Masking slider combination reduces the image to a lithographic-like image letting you choose the level of sharpness on wide to narrow edges within the image.
The final two boxes allow you to correct inherent camera faults, such a chromatic aberration and lens vignetting, as well as letting you calibrate your camera's sensor for accurate colour. The latter is too in-depth for this article, but the Lens Corrections box certainly has a useful tool in the vignetting section. Although primarily designed to correct darkened corners in images, creatively it can be used to add vignetting, whether light or dark, and to give images a vintage look. The Midpoint slider reduces and enlarges the middle of the vignette, while the Amount slider determines the lightness or darkness of the image corners.
By using a combination of the controls in Lightroom, I've drastically changed a cute picture into a very commercial and saleable image. I can now very quickly apply those settings to other images in the collection by selecting the new images and synchronising them with the first. Of course I'd recommend then tweaking the new images individually as well, as slight changes in the exposure can have a major effect, but this takes less than half the time it would take to do individually in Photoshop. Alternatively I can save the new settings as a preset by going to Develop > New Preset. I can then name the preset and save it in my User Preset file and quickly add it to any picture I want in the future.