Keep the brush as small as you can when highlighting edges to minimize your work later. Wide enough to cover your edge, but not so wide that it requires a lot of touchup.
Follow the edge with some care, and use smart highlighting wherever there is a reasonably defined edge to follow. Smart highlighting hugs edges and increases/decreases the size of the application brush automatically.
Use the magnifying glass to zoom in close (click the icon or press Z), and the Hand (click the icon or press H) to move the picture once you are zoomed in.
Trim both inside and outside the highlight edge as close as possible to the edge that you want to retain.
Don't be afraid to stop and touch-up as you go with the Eraser (click the icon or press E) and use Undo (press cmd/ctrl + Z) whenever you make a mistake.
If there are breaches in the highlight outline, the fill may stray into unwanted areas. If the Fill covers more than you want, undo the fill, fix the highlighting, and fill again.
Use the Edge Touch Up to remove frayed areas and stray pixels. The tool both adds and removes information to the preview by altering the mask.
Use the Clean Up tool with a small brush to get rid of background that seeps in to the selection. Add areas back by holding the Option/Alt keys (Mac/Win).
Switch views between the mask and extracted result as necessary to improve your results. To see the mask, choose Mask from the Display option on the Preview section of the screen (Preview>Display>Mask), after you preview the image (Step 5). This will show you the mask that was created by Photoshop, which it is using for display of the preview. You can then, if desired, retouch the mask using the Clean Up and Edge Touch Up tools. You can also retouch while previewing the result (Preview>Display>None). This will give you a visual sense of how the mask directly effects the result as you retouch.
While the tools in the interface are somewhat similar to other Photoshop tools, or at least function somewhat like familiar tools, the function of these tools are helpfully targeted to making complex masking easier. Keying on the function of each tool and the advantages it offers will help you master the interface and the results. The following table provides an overview of the tools and how to use them.