did. Did is wrong if you mean have.
Wrong. I didn’t see him yet.
Right. I haven’t seen him yet.
each other. Each other applies to two persons or things; one another to more than two.
extra. Extra does not mean unusually.
falls. Plural, not singular.
first-rate. An adjective, not an adverb.
Wrong. You cook first-rate.
Right. You are a first-rate cook.