I aws constantly plagued with doubts about some of their teachings -Jesus being michael- dates -prophecies that seemed to apply only to the witnesses of this century-Blood issue-birthdays etc etc .
But what really helped me to see that this is was not the truth was (when i was at a low ebb where i was having marriage difficulties) the internet when i took the courage to overcome my fear of reading some non witness information on 607 BCE and discovered that it is unfounded .It really began their and i became addicted to reading all about the WT past and all the failed dates etc.