#1 Forget about Madrid - press hard, play the ball early to Salah.

Or Klopp could do what Real Madrid do most of the time... forget about the opposition and give the ball as soon as possible, as often as possible, to their best footballer.
The Reds are in the Champions League final because they played football they believed in (mostly, apart from spells against City where they parked a pretty darn big bus) and they shouldn't back down from their principles. In this Clasico, Barcelona showed that (down to ten men or not) if you play your own football against this Madrid side they can be troubled... Barca especially picking them off the counter.
If Liverpool play their natural game and play the ball early - and often - to Mohamed Salah (who is smack bang in the middle of the mother of all purple patches and will be up against the tempestuous Sergio Ramos along the inside-right channel) there's no reason why they can't come out on top against the 12-time Champions of Europe.