Are you talking about 3N-4-3 if yes then,

Red arrows on ML, MR, 2 ST and Blue on middle DC

And I am assuming that your opponent is stronger in that case go with attacking mentality, mixed passing (lot of ppl will say passing down both flanks but I prefer focused passing to be mixed while playing 3 4 3 because it helps your MC to perform better), whole pitch, tackling hard, no to counter attack and yes to offside trap ( offside trap works best with 3 DC).

What is your opponent formation and quality? Lot depends upon that as well.