I am not English but I do understand what he meant.
He wanted you to AVOID or REPLACE the word NOT.
Personally I found it very difficult to actually "do" in everyday life.
Do not use n't words like can't, won't doesn't, isn't, shouldn't.
The word NOT is useful an carries numerological total of 4.
BUT when you drop the letter „o” as in N'T, the numerological tries to become total 7, but is not 7, and N'T stays 5 (for the N) and 2 (for the T)....
The combined occult effect of N'T words is to put sign which says uncertain decision ….
Whenever you find yourself using mysterious N'T words,
replace that words with a different word, or rephrase it the thought to avoid the N'T word altogether.
Also reduce the number of NOT's in your thoughts.