If you're going to design or edit palettes, it helps to have good color sense, so...I'll break it down to a quick palette guide for those of you who don't feel like going to the ZC tutorial...
Okay, for example, you're making CSet 7 in a completely different graphics pack....you need colors for Link, items, and other sprites.
If you want to add a lot, I'd recommend starting with the Classic set, because there's a lot more room for adding stuff...
now for your colors...
The first three you should leave alone, since Link has grabbed those, and you'll end up having to mess with CSets 6 and 8...
If you want to have some really good items and sprites, I recommend going with a balance of colors...a few blue, gray, and maybe some gold and brown...
To actually start building the colors, you must have an understanding of RGB values....
It's just like the acronym...(Red Green Blue)
00 00 00 being black and 63 63 63 being white...
It's a great deal easier if you understand what colors make other colors...
Red and Green make Yellow....Green and Blue make aqua, and so forth...
For the browns, use more red than green, and for gray, use all colors, but not at maximum, like 30 30 30 or something.
It's best to experiment with various combinations. If you fool around with the palette editor enough, it'll become second nature.
EDIT: Oh, and if anyone needs any more help on palettes, hey, you're talking to the man.