These are fun ones and are very often misused. I think the easiest way to differentiate is to just write sentences with them.
Peek a boo! I see you!
The peak was over six thousand feet high.
The concept piqued the child’s interest, so they gave the child more to study.
We played peek a boo with each peak as it peeked around the corner; it was just enough to pique the toddlers interest and kept zir attention.