If you regularly create puzzles using the same word list you might like to avoid words that you have used before. You can do this by changing the scores of the words in the word list each time you have made a puzzle. Alternatively you might want to add words in a puzzle to a word list.
To do these things select Change scores of words in puzzle from the Words menu and select the word lists that you want to change. You can either change the scores by a certain amount, or set the scores to a specific value.
By setting a fixed low score for the words' scores you can cut them out of future grid fills completely by setting the minimum cut-off score to above the score which you have given the words.
By just decreasing the scores by some amount you can ensure that AutoFill and Fill Grid give a low priority to words that you have used most often before.
Click the Add words not in list box to add words to the list as well as changing the scores of words that are already in the list. If you just want to add words without changing the scores of words already in the list you can set the Change scores by setting to zero.
If you only want to change some or specific word scores, use View/Edit words and scores on the Words menu.