First of all, they need to be good liars. 

Second, they need to be blind to reality and good at making you think you are blind, too.  Just as blind as they are.  "You aren't really seeing what you think you're seeing".  That's the new mantra of the leftist "gang minded politicians" who are amongst the biggest sell-outs in world history.  But the lies are the worst part and people are finally starting to "get it".  Sometimes reality has to smack you in the face before you start paying attention.

https://thefederalist.com/2022/02/01/these-top-economists-insisted-inflation-wouldnt-happen-until-the-numbers-made-them-look-like-fools/

The dimwit dems were all as excited as a "herd" of cats in a thunderstorm until their plans started to fall apart, little by little.