How to agree with an opinion

Our group has been preparing for our presentation of speaking, and my part is"How to agree with an opinion" . So I have read some book and searched the internet to find some useful expressions or functions. There are some ways that you can use:
When you strongly agree with an opinion, you can say:
"I couldn't agree more! "
"That's exactly what I think"
"That's exactly what I think"
Or some simple ways like:
"That's absolutely true! "

"I agree with your point"

Or you just say "absolutely"

And sometimes people also say :

" I'd go along with you there"

" I'm with you on that."

" That's just what I was thinking"

" That's a good point. "

" That's just how I see it"

If you just half agree with an opinion, what will you say?

I will tell you some ways :

"Hmm, possibly, but ..."
"Yes, perhaps, however ..."

"Yes, in a way, however ...
"Well, yes, but ... "

When you would like to say that your friends have their point but what you think is not totally similar , you can say:

"Well, you have a point there, but ..."
"There's something there, I suppose, however... "
"Yes, I suppose so, however ..."
"I guess you could be right, but ... "

Or some times you can say:

"That's worth thinking about, but ... "

So I hope these ways are useful for you , and you will find it is easy to show your agreement with an opinion.

(source : www.paulnoll.com/Books/Clear-English/debate-suggestions )