Ignore rare, difficult suffixes. But don't miss common and easy ones.
Here is just a demo to show how much you stand to gain if you pay a little attention.
-er(-ar, -or, -yer), - doer
painter, baker, lawyer, jeweler, driver, teacher, dancer,
helper, farmer, lawyer, jeweler, preacher, prisoner, villager,
officer, trainer, trainer, villager
emperor, sailor, protector, narrator, translator,
investigator, conductor, distributor
scholar, beggar.
-eer, - doer
volunteer, engineer, musketeer, auctioneer, racketeer, mountaineer, profiteer.
-ee, - person who takes a passive share in an action
employee, payee, legatee, mortgagee, trustee, referee.
-ist, a person who follows a certain trade, person who practices
scientist, chemist, psychologist, physicist, cartoonist, columnist,
bicyclist, cellist, violinist, pianist, theosophist, artist, plagiarist,
narcissist, nihilist, terrorist, atheist.