When you are winning the trick to score loads of goals is not make subs too early. Try to stick to your starting 11 and more often than not they will add to the tally. That is why you score more when u don't watch. I suspect that a lot of managers make changes by the 60th minute, which disrupts the simulation.
For example at 4-0 up, what happens to me usually is whn I make a sub in the 60-65th minute, my team stop scoring. But if I wait for the 75th minute, I would probably be 6,7,8-0 up.
Back to the topic, I've beaten someone who had a stronger squad and was 3 levels above me (7-0 & 5-0), but apparently he was inactive for more than two months. He became a bot not long after that. LOL.
On the contrary, I've found a substitution has often spurred the team to score where they have been drawing a blank previously...
Any formation or tactics advice given is based purely on experience with my teams...