You have 4 groups of 4, but the puzzle element is missing.

To improve your want to have at least two (ideally more) that fit into other groups. You also want the way they are connected to be different.

Take May from your grid. May can be a month, a prime minister, last word of a TV programme starting David Jason (darling buds of may), an anagram of a vegetable/tuber (yam), precede the word fly etc.

Good options include anagrams, words within words, words that follow/precede a common word, synonyms, as well as words that fit a category such as yours do.

Good luck constructing.

Very nice! :) enjoyed x