Compliment or complement
Example:
You pay someone a compliment. You have a full complement of students.
A book review might be complimentary. Two types of medical treatment or two colours can be complementary.
Comprise or compose
Example:
The parts compose (make up) the whole. The whole comprises (includes) the parts. The whole is composed of the parts. Never use is comprised of, although consists of is correct.
Fewer/less
Use fewer when the amounts can be quantified, less when they can’t:
Examples:
There are fewer than 10 places available
There is less milk than yesterday
It's or its
It's means it is.
Its means belonging to it.
-ise or -ize
Use -ise rather than -ize in words such as organise, specialise and finalise.
-ize is generally used in the American spelling of words.
Liaise and liaison
Note the correct spelling. Some spell-checking functions get this wrong.
Examples:
The professor will liaise with other faculty members to organise a conference on sustainable development.
The student ambassador acts as a liaison between UL administration and the student body, addressing their concerns and feedback.
That or who
Use who when referring to a person. Use that when referring to a class or type.
Examples:
She is the only student who lives in Kilmurry.
He is the type of lecturer that enjoys teaching.