First, when you express an opinion, do not identify yourself with this opinion. The difficulty is exactly because people identify with their opinions. Two, say

First, when you express an opinion, do not identify yourself with this opinion. The difficulty is exactly because people identify with their opinions. Two, say "as far as I know" or "with the data I have now" and follow with your opinion. It makes backtracking much easier. Third, when you express an opinion, communicate what it is based on. It makes for much more interesting conversations. At least, those are my observations on others and myself.