I'm a good speller, but even I get some words confused. When is it "peek," rather than "peak," and vice versa?
I ran into this problem while editing Why My Love Life Sucks: The Legend of Gilbert the Fixer (book one). It's lucky that I noticed it, because it's not the kind of thing spell check picks up.
As a visual learner, I realized the best way to remember which one to use is with a drawing.
Peek has two Es, which are like two eyes peeking. If you can see the eyes peeking, you've spelled it right.
Peak, when spelled with a capital A, has a peak in the middle, like a mountain peak. Remember that the A in peak is a mountain peak, and you'll get that one right too.
Pique has a Q in it, and a lowercase q looks like a monocle. Think of someone wearing a monocle whose curiosity has been piqued. If it helps, think of the i in pique as an upside down question mark asking, "What is that? It piques my curiosity."
peek, peAk and pique: now you can tell which one to use when.
I hope this helps you too.