I always have been having problems how to understand which preposition to use. Of course there are examples, in which the preposition is obvious. For me the problem occurs when "Do your best in/on/at x." means "Deal with x as effectively as you can.". Which grammar rules or methods should I use for this case?
I'll do my best on the TOEFL preparation so I'll get a higher score on the exam.
I'll do my best on the test tomorrow.
Do your best in achieving this goal.
Do your best in the planning of our weekend.
Do your best in filling out the form.
I see these questions for the first time so I haven't prepared for them. Should I just do my best to guess the right answers?
You will have only 15 seconds to prepare so do your best to use them effectively.
Should I ever write or say "I will do my best at x", when I use it in the meaning "I will cope/deal with x (as good as I will be able to)"?
That's a "trick" question because it is not about what follows "best", but simply about "should you use 'in' or 'on'?".
The double-trick is that in some case, you could (with a slight variation of context) use 'for'!
I'll do my best for the TOEFL preparation so I'll get higher score on the exam.
Meaning I don't find your examples "wrong".
Do your best in all your endeavors.
Do your best with the tools you have.
Do your best for the team.
Should I just do my best in guessing the right answers?
You will have only 15 seconds to prepare so do your best in using of them.
Should I just do my best to guess the right answers?
do your best to use them effectively.
In that last I removed the "of" and added "effectively," which seems clearer and stronger.
EDIT: I removed some examples that wandered away from Preposition Land. Thanks to Ito and fiktor for pointing out my brain cramp.
The 'in', 'on' or 'for' can change because they are not the postpositions of the expression 'I'll do my best...', but the prepositions of the expressions afterwards, like 'on the TOEFL' or 'for the TOEFL'. So they don't change according to the preceding part of speech but the following one.
"consolidate on" or "consolidate into"?
How do I address people who give feedback?
Is it normal to use "absent" as a preposition instead of 'without,' or 'in the absence of'?
When referring to parties hosted for players should you use an apostrophe? How if so should you use it?