It is a good question about enhancing the vocabulary.
But the answer would be different depending on each individual person and their current level of English vocabulary.
For grade 12 student or adult, most probably reading a lot of books will be the best way to expand vocabulary.
If we are talking about child studying at first grade or an adult who learns English as a second language, it is necessary to use several tools to work on vocabulary. It is easy for parents to forget that learning is not an automatic process. Instead, it is a complicated process that needs support and different tools to achieve progress.
I may recommend a couple of articles which may advise more on how to build vocabulary: