It’s / Its
It’s : contraction of “it is”.
Its : possessive pronoun or adjective.

 
Fewer / less
Fewer : nouns that can be counted.
Less : nouns that cannot.

 
Accept / Except
Accept : receive.
Except : not including.

 
Lie / Lay
Lie : intransitive verb.
Lay : transitive verb (past tense of lie).

 
Flair / Flare
Flair : skill or talent.
Flare : a sudden blaze.

 
Compliment / Complement
Compliment : an admiring remark.
Complement : goes well together.

 
Emigrate / Immigrate
Emigrate : leaving.
Immigrate : coming.

 
Flammable / Inflammable
Flammable : inflammable (liable to catch fire).
Inflammable : flammable (liable to catch fire).