Important factors in deciding tone and what to say:
1) Strength of opponent vis a vis your team.
2) Home or away?
3) Watch the match at least on "extended". What is your team doing?
4) Score?
5) Assistant's input.
6) Are there any individuals "looking complacent" etc (if so deal individually).
So you are Utd playing against WBA away winning 2-0 down to 10 men:
1) At UTD you most likely have a v good assman ... so look at what he says. Here "room for improvement".
2) You are the better team and you are playing away and that would seem that "dont get complacent" wouldnt be a bad thing to say, but the 10 players thing together with what the assman says as well as what the match probably showed (and also the team mentality - very top team players tend to be extremely touchy) would indicate the following approach:
a) Doing well, keep it up, general talk. Passionate
b) Positional team talk : assertive you can do better.
c) Individual talk as above.
Actually whatever you say to the team I find that positional team talk as above is always a good idea.
