If you are efficient you work well without wasting time or energy.

As he was efficient he was promoted.

If something is effective, it has the desired result.

Those pills weren’t effective. My headache isn’t any better.

Especially and specially

Both especially and specially can often be used with the same meaning.

It is not especially good. OR It is not specially good.

Especially can mean ‘above all’.

I do a lot of gardening, especially on Sundays.

I like all kinds of fish, especially salmons.

Specially can mean ‘for a particular purpose’.

These skirts were specially stitched for me.

Especially goes after a subject.

All of us like football. My father, especially, goes to as many football matches as he can. (NOT Especially my father …)

Ever, yet and already

These words have different meanings. Ever means ‘at any time in the past’.

Have you ever been to New Zealand? (= At any time in the past)

Yet refers to time around the present.

They haven’t arrived yet.
Have you been to New Zealand yet?

Already means ‘earlier than expected’.

I have already been to New Zealand. (The trip has taken place earlier than expected.)