just concentrate on remembering the harder ones that make no sense, like ORD (Chicago) , MSY (New Orleans), and CVG (Cincinnati). The one I always had trouble with was SDF, for Louisville, til someone told me it stood for Sam Davis Field
SDF=
Stan
di
ford actually. ORD=Orchard Park and MSY=Moissant Stock Yards, both original names of the airfields. CVG because it's located in
Co
vin
gton, Kentucky.
And I imagine you only have to memorize those cities served by your airline (HP, WN ?), which makes it easier.