In multiplayer if someone is playing T.Keeper, you will dive for the coins risking damage. Coins trump everythings. For Angel/Devil room save at least 30 coins, preferably 45 in case Devil offers good 30 coins item and good enough 15 coins item. Only the first item in boss drops costs money, the rest are free.

Kick T.Cain players in lobby, no need to humor them. If you see someone picking T.Lost, do notice you won't get HP up items, so you have to rely other means of raising health like HP up pills, Balls of Steel, Hierophant, any item that has secondary HP up and so on.

Devil Deals are better in multiplayer because more players, more health. Also more players, more chances to lose the Devil/Angel room chance anyway. You can use your excess health on Sac Rooms to produce Megan Satan key and chance to teleport to Devil/Angel room.

It's good to emoticon bomb before using bomb because other players might not pay attention to using bomb otherwise.