Could you please explain me this phrase:“I think we have to be very careful in all of this that we don’t write off somebody else’s approach.” Thanks a lot.
“that we don’t write off somebody else’s approach”
You can replace “write off” with “dismiss.” Writing something off would be to disregard it, throw it out, or dismiss it.
So it’s saying that they should be careful not to overlook somebody else’s idea (or in this case - approach). A reason for this might be because it may actually have some use if you looked at it more carefully, or there may be something you can take from it.
So, if you told me your method for learning English, all the different things you do etc, I do not agree with all that you said, but I might be careful not to immediately disregard (write off) what you said since there may be elements in it that I can implement myself. Or perhaps I’ll look more in depth at it and realise that it’s a good method.
Hope that helps.
“I think” = I believe = In my opinion
“we have to be very careful” = be we should be cautions = we must be wise
“in all of this” = in this matter = under these circumstances = concerning this matter
“that” = that =
“we don’t” = we don’t
“write off” = discount = ignore = dismiss
“somebody else’s approach” =someone else’s way of doing things. = another person’s way of meeting the objective
I hope this helps, Claude! 
That sentence would not be so difficult to parse if it used a slightly more formal grammar:
I think THAT we have to be very careful in all of this SO that we don’t write off somebody else’s approach.
Thank you very much for your explanation