what does this mean "make every word tell"? I don't get it.
Thanks a lot
Don't use a word unless it adds something. Eschew obfuscation.
"Make every word tell" is BrE in my opinion. In AmE we would say "make every word count." To employ another AmE idiom, it means don't waste a single word, i.e. even one word. Each and every one of your words should carry its own impact.