Whenever something seems to be moving towards a TPK, I make sure the players have some sort of reasonable escape. There may be one or two PC deaths, but nothing crazy. I think I ran OOTA with only 2 PC deaths for the whole campaign.
The other thing is that OOTA specifically gives you lots of NPCs at the start so they can take the brunt of the deaths.
Whenever something seems to be moving towards a TPK, I make sure the players have some sort of reasonable escape. There may be one or two PC deaths, but nothing crazy. I think I ran OOTA with only 2 PC deaths for the whole campaign.
The other thing is that OOTA specifically gives you lots of NPCs at the start so they can take the brunt of the deaths.