prescribe, proscribe
prescribe means to recommend a remedy
proscribe means to prohibit

principal, principle
principal means a leader
principle means a truth

stationary, stationery
stationary means immobile
stationery means paper you write on

orient, orientate
orient means to give direction
orientate is used in the U.K.

precede, proceed, proceeds
precede means to come before
proceed means to move forward
proceeds means money

predominant, predominate
predominant means more dominant [adjective]
predominate means to dominate by superior numbers

lead, led
lead means to guide
led is the past tense of lead

leave, let
leave means to depart or allow to remain (Leave me alone. Leave it on the shelf.)
let means to allow (Let it sit on the shelf. Let it be.)

may be, maybe
may be means it is a possibility [verb phrase]
maybe means perhaps [adverb, so it needs a verb]

incredible, incredulous
incredible means not to be believed (That’s an incredible story.)
incredulous means skeptical (I was incredulous of the story.)

irregardless, regardless
irregardless is not a word
regardless means having no regard

issue, problem
issue means many things (e.g. latest issue) but does not mean a problem
problem means a difficulty to be dealt with

historic, historical
historic means an important event in history
historical means dealing with the subject of history

impact, impactful
impact does not  mean to affect something [use affect or influence]
( This affect the team, not, this impact the team.)
impactful is not a word [use effective, forceful, compelling, impressive]
(The seminar was effective, not the seminar was impactful.)

imply, infer
imply means to suggest indirectly
infer means to conclude

[The first set of words was to be good and well but that is more than I wish to tackle at the moment. I'll cover them in a future post.]

hanged, hung
hanged means executed by hanging (The criminal was hanged)
hung is the past tense of hang (I hung the curtains)

healthful, healthy
healthful means something that contributes to health
healthy means free of disease

flaunt, flout
flaunt means to show off
flout means to ignore

flounder, founder
flounder means to move clumsily
founder means to encounter trouble

gone, went
gone is used following have or has (I should have gone with them.)
went is the past tense of the verb to go (I went to the store.)

emigrate, immigrate
emigrate means to leave a homeland
immigrate means to arrive in a new homeland

eminent, imminent
eminent means distinguished
imminent means about to take place

fewer, less
fewer is used in reference to things you can count (pens, pencils, etc.)
less is used in reference to time, money and distance
less is used in reference to things you can’t count (water, rice, etc.)

drug, dragged
drug pertains to a medicinal substance, not a pulling action
dragged is the past tense of drag (I dragged myself out of bed.)

due to, because of
due to modifies nouns (The game postponment was due to rain.)
because of modifies verbs (The game was postponed because of rain.)

elicit, illicit
elicit means to bring forth (I tried to elicit a response.)
illicit means illegal (The drugs were illicit.)