Небольшая подборка полезных фраз, которые понадобятся если вам придется выражать собственное мнение на английском:

I (really) feel that...

In my opinion...

The way I see things...

I tend to think that...

I believe that

As for me, I feel that

I consider

I suppose

I guess

I ‘m sure that

I’m confident about

To my mind

I agree with the point that