Palette: the board on which a painter holds and mixes paint
Palate: the roof of the mouth; also, the sense of taste
Pallet: a wooden frame on which goods are loaded
So how to remember the difference?
A palette has lots of letters (compared to the other homonyms) and lots of colors!
Your palate is what makes you want a hamburger late at night.
A pallet (the only homonym with two l's) has l-shaped boards.
Cheesy, I know, but you'll never confuse them again!