Our testers loved this tetris-word search hybrid puzzle set, but words like swami and kudzu were beyond our kid-testers' vocabulary. That made it difficult to solve some puzzles, as it was entirely possible to solve the puzzle without even realizing it, say for example, if you didn't know that the last three letters - eg. F E and Z - are actually a real word.
Our suggestion is to provide your child with a master list of words to use as a reference. You can even be a little tricky about it: include a few extra words not on any of the puzzles, and leave out a number of the commeon words that are. Since they don't know which words might be in any given puzzle, you aren't really giving hints so much as bringing your child up to speed with the vocablary - especially if you also tell them what the unfamiliar words mean.
Solving the puzzle is a matter of searching through the letter grid to find the word shapes to match the translucent tetris-like pieces you're...