Here's a picture of the top of a fret crown after being filed (notice that it's flat):
After leveling, you have to restore the domed top to each fret using a fret file (which is basically a file with an inverted dome shape cut into it so that it cuts a gradual dome as you use it). This tool typically runs about $40 or so, but you MUST have it.
Fret leveling doesn't really pose a risk to the fingerboard if you're careful, but fret crowning and end work does. It's best to tape off your fingerboard and protect the lacquered instrument before starting. It turns out that Pop-Tarts are both delicious AND useful...
Once I had the frets re-crowned, I needed to turn my attention to the fret ends along the fingerboard. If I had left them as they were, it would be like playing a razor blade guitar from hell and there'd likely be a fair bit of blood involved.... The fret ends should be smoothly beveled and flush with the fingerboard edge--basically they should not cut you when you play.
However, I made a mistake when initially installing my frets. My fret wire came in 2' long straight pieces, and my fingerboard has a gentle radius to it. I SHOULD HAVE gently bent the frets into a curve so that when pressed into the fingerboard, their inherent springiness would force the fret ends downward onto the fretboard--(because my maple fretboard binding is fairly wide, there is a large amount of fret overlapping it that does not contain any fret tang to hold it in place).
Here's the problem (in it's most exaggerated form):
I eventually remedied these with the careful usage of clamps and superglue, but I still wasn't happy with the way the fret ends were turning out....
...so I got an idea. A friend of mine has a guitar built by a professional luthier who actually rounds the ends of his frets into these perfect little half domes--it's unreal. Apparently he does so BEFORE he installs the frets. Mine, however, were already in place....BUT I figured since the ends didn't quite seat against the fretboard and since I didn't like where it was going, I might as well try to round each one off...
...and it worked! One of the better on-the-fly decisions I made. That move completely transformed both the way the frets looked and played, as well as how I felt about the whole thing. It took me about 3 hours to round all 44 fret ends, but it was time well spent.
I found that after filing with a fine needle file, the frets were actually in pretty good shape. I finished them off with some aggressive #0 and then #0000 steel wool polishing. I think I did a good job--but not great. Had I wanted to spend the time with progressive sand paper grits and work up to a #0000 steel wool then I think it may have been more shiny, but I figure with strings on it and general use, they're pretty good. I also tried a final attack with a Dremel and some polishing compound--that actually worked really well, but it makes a lot of runny black residue so be careful when you tape things off.