Let’s face it. EDH is a format in which pretty much anything can happen. Inevitably, one of those things will be a mistake. Okay, so there’s often lots of things that can go awry in games of Commander. Thankfully, some of those mistakes can be avoided before the game even begins with responsible deck building.
Here are three common mistakes in EDH deck building that you should avoid:
Mistake #1: Forgetting about card advantage
Whether by cantrips, modes, or two-for-one punches, card advantage can be had in nearly any EDH deck fathomable, so it’s surprising that so many Commander players either forget about or severely underappreciate the concept.
Probably the most obvious source of card advantage is via card draw engines such as Mind’s Eye, Phyrexian Arena, Rhystic Study, and the like. Card draw (especially efficient card draw) is rarely ever a bad thing. Cards with cantrips (eg: Arcane Denial, Benefactor's Draught) as well as those with the buyback ability (eg: Capsize, Elvish Fury) also somewhat fit in here as they replace themselves either by providing you with card draw or by simply returning to your hand after resolution.
Card advantage can also be had through recursion. Cards like Debtors’ Knell, Sun Titan, Phyrexian Reclamation, and the like all give you card advantage by repeatedly bringing cards back either into play or back unto your hand after they’ve been lost for one reason or another.
Finally, having a card that either does more than one thing (eg: Fiery Confluence, Funeral Charm) or give you more than one thing per card (eg: Lingering Souls, Decree of Justice) will give you that two-for-one punch. In a way, it’s almost like adding extra cards to your deck and in your hand by means of options and spread effects.
After all, nobody likes being the player with only one card left in their hand and one option at their disposal when everyone else has plenty.
Mistake #2: Not enough mana
This common mistake goes two ways as we’re talking about not just having enough lands in your deck, but also enough non-land mana sources such as mana dorks, rocks, and so on.
In terms of actual physical lands, keep in mind that 60-card constructed decks typically run between 22-24 lands. That’s 37-40% of the deck. Your Commander deck should run approximately the same 3:2 ratio of non-lands to lands, which comes out to 38-40 lands in your 100-card EDH deck. If you cut that number too short (say 32 to 35 lands), you’re going to run into trouble – especially when you consider that Commander typically has a higher mana curve than most constructed formats.
Of course, it doesn’t just stop with land cards. You also need to keep in mind ramp (and we mean more than just tutoring for lands with cards like Expedition Map, Renegade Map, and Sylvan Scrying). Mana rocks (eg: Mana Vault, Sol Ring, Boros Signet, etc.), mana dorks (Llanowar Elves, Vodalian Arcanist, Sisters of the Flame, etc.), and the like all come into play here. In a format where it’s not uncommon to cast six-, seven-, and eight-drop spells, these non-land mana sources will help get you there quicker and with better consistency.
As ludicrous as what you’re about to read may seem, it’s sound advice: Roughly half of your EDH deck should be able to produce mana one way or another. And, unless you’re running a deck with a very low curve such as a Kytheon white weenie deck or an Edric political evasion deck, running 46-50% mana sources is probably where you want to be. It will keep you out of trouble of being mana screwed and will give your decks better regularity game-in and game-out.
Mistake #3: Discounting interactions and answers
Let’s say you’re playing a tribal-themed EDH deck (for the sake of argument, we’ll make it goblins). It is super easy to search out all of your goblins and “goblin matters” cards to build an on-theme deck full of cards like Goblin King, Goblin Ringleader, Krenko, and so on. It’s equally as easy to overlook off-theme cards that would otherwise provide your deck with the sorts of answers and interactions needed to keep you in the game.
When building a deck, save about 25% of your 60-64 non-lands (that should be roughly 15-16 cards) for not-on-theme interactions and answers. For our “goblins matter” example, that would mean saving space for cards like Anger of the Gods, Pyroclasm, Shatterstorm, Chaos Warp, and so on. And if you can have answers that are on theme, that (to a point) is even better. These are the cards that allow you to respond and react to what your opponents are doing. Without them, you’re going to have a bad time regardless of how meme-worthy on-theme your deck is.
The other 75% (45 or so) of your 60-64 non-land cards will be where your deck’s theme go whether that be tribal, “X-matters,” or simply cards designed to play will with your commander.
It's kind of like the Commander deckbuilding way of having your cake and eating it, too.
EDH is about fun games and if you make key mistakes in deck building that have serious repercussions on how that deck plays, you’re not going to be having a lot of that fun. And if you’re not having much fun, your play group probably isn’t either. So take the above advice, build yourself one heck of an EDH deck, and go have a blast playing games of Commander.