Sugars and calicos are very similar, but there are a few traits that are different, consistently. Remember, they won't all look exactly the same. Consistency is what separates them.
Sugars tend to have black backs and wide alien heads with no dots. This is a typical high quality sugar IMO. Obviously the highest white would be best.
Calicos tend to have thin alien heads with many dots and a banded pattern. The calicos seem to have a lot more highlighty orange along the pattern, typically near the tail. Again, not ALL calicos will look like this, but I've consistently seen calicos have these traits.
From what I've seen, calicos and sugars both throw random amounts of white, just like the pieds. If I find the thread that had some good pictures and info on them, I'll link you

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Here's my calico (low/medium white):
Notice the thin bands and lots of dots. Also notice that she is definitely not a black back lol.
Here's a clutchmate that sold too quickly

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Bright orange trim, lots of dots, however, he expresses the blackback trait.