Key phases

I think / I feel / I reckon / I guess (informal)
In my opinion / in my view (formal)

Apparently / so to speak / more or less / sort of / kind of (informal)
Well / really / that is to say / at least / I’m afraid / I suppose /  rather / actually / I mean

The expressions I think / I feel / I reckon / I guess / in my opinion / in
my view etc are used to make opinions or suggestions sound more polite. They suggest that the speaker is just giving his / her opinion with which the
hearer may or may not agree.

I think we should try again.
I feel she is making a mistake.
In my opinion / view it would be better to try again.

Apparently can be used to introduce a piece of information the speaker got
from somebody else. It also suggests that the speaker cannot guarantee the authenticity of the information.

‘Have you heard?’ ‘Apparently Joe is going abroad.’

The expressions ‘so to speak’, ‘kind of / sort of’ and ‘more or less’ can be used
to give the impression that you are not speaking exactly.

I kind of think that he is a fool.

The expressions ‘that is to say’ and ‘at least’ can be used to say something
less definite after you have made a strong or definite statement.

Ghosts don’t exist. At least, I have never seen one.

I’m afraid can be used to introduce a polite request or bad news.

I’m afraid there has been an accident. (= I am sorry to tell you that there
has been an accident.)
I’m afraid I can’t help you.