Here's a simple game that will help you.

Get a friend to choose an ordinary word from your Esperanto dictionary, say 'pagi'. Your task, to say what komun-lingva word follows in the dictionary. So we ignore technical terms and the names of obscure plants fishes etc.

In my example you might think 'paĝo' is the answer. Wrong!

Give yourself a point if you thought of 'pagano' (pagan), or 'pagoda' (pagoda). Two points if you remembered 'pagajo'

Test yourself again after several weeks. You should find that you still remember one of the words you missed on your first attempt.

Hello,

The rules have to specify how you exclude technical words - what is an obscure plant? - and if you accept kunmetaĵoj - Is "pagado" or "pagaĉo" convenient?

Of course you can play just for fun and agree about unfairness of a too easy answer, but it is more challenging if the rules are precize.

If the players agree to use a dictionary, it is easier to count points negatively, one point for each word in the interval, and zero point if you found the exact word.