Composition
The comp double DK (mostly Frost) and Protection Paladin is insanely strong mainly due to the fact it can counter most other comps.
Against double melee, while staying on the enemy healer, you are able to affect the whole enemy team with double their usual cooldown recovery thanks to
Пелена зимы. It is also quite easy to stick to the enemy thanks to double grip.
Against casters, you have two
Зона антимагии that can nullify their kill attempts, as well as a large amount of immunities. Death Knights also excel in self sustain against burst damage thanks to
Удар смерти. So the offhealing potential of a Protection Paladin is enough to keep them alive.
Protection Paladin is overall similar to an offensive type healer, we have less overall healing but more immunities as well as shutdowns (silence, knockbacks, as well as having an Interrupt). This is really helpful for your kill attempts when you combo double
Мертвенная аура into double
Поток холода since you can shut down the healer during that time.
Playing double Unholy is also really strong, but weaker against melee since you might have survival issues. However stronger against casters if they really attempt to avoid
Поток холода.
Strats that seem to work well
Rogue / Mage / HealerAgainst this, focus on the healer. Your team will have enough immunities and survival to outlast their burst attempts (if you use them right) You will also be able to lockdown the enemy healer and force defensives thanks to all your interrupts. This was one of the easier comps to face.
Warlock / Caster / HealerAgainst this, Unholy worked much better than Frost. No matter how your setup is, splitting one Death Knight on each enemy caster is great to reduce their pressure. Your strategy in this case is to make the enemy healer go OOM, or find opportunities when you can all shift onto one target and kill it while enemy healer is in a stun - silence chain.
Melee / Melee / HealerThis can be harder depending on the enemy DPS, if they are cooldown reliant or not. The usual strat is to go on the enemy healer but be ready to do sudden shifts onto the DPS incase the enemy team is peeling too much, or you are unable to keep up momentum (or if they are a ghost wolf shaman)
I won't be able to list every tactic against every comp, and it will differ a lot depending on the enemy teams playstyle. A lot of teams can get confused facing a double DK / prot pala team and be unsure who to target etc, use this to your advantage.
(I will obviously not list our weaknesses here)
Try out-zerging the enemy healer in most scenarios and see what works and what won't work for you! Make sure not to get locked onto one strategy all the time since at different ratings people might become better at countering a certain strat.
Running out of space but quick notes:
Gearing
CorruptionsPaladin Talents/EssencesDeath Knights