I started playing Magic about a month ago and I've been playing with the Underworld Herald event deck while I get used to the game.

However Underworld contains cards from M14 and the Ravnica block which will be rotating out soon.

Would anybody be able to give me some tips or general advice on what I should do with the deck to keep it legal for standard when Kahns is released.

Thanks!

Sadly the practice of "getting ready for rotation" just means keeping a keen eye on the spoilers (which should start in the next few days) and then trying to figure out the best, most suitable replacements for pieces that are rotating out. There isn't any one given way to do it... sorry.

I agree with TyWoo. If M13 with Lifebane Zombie and Theros with its devotion mechanic have taught us anything, it's that you have no idea what each new set can do to established archetypes and potentially strong Block decks.

I would suggest you hang tight with your Hero's Downfall(s) and Herald of Torment(s) and see what Tarkir brings.

I would definitely concur that you should pick up Theros staples at the moment while they're super cheap as, for all we know, there will be a deck out there that breaks some of the cards. Hell, I've even seen speculation that Xenagos, the Reveler could actually increase up to like $20.

But as far as deckbuilding, look to the theros block constructed stuff, supplement with M15, and just be patient.