In the world of Commander, determining which cards to include in your deck can be difficult. Many of the best rules and methods players apply in other constructed formats mean nothing here. Cards that are amazing in Legacy may only be mediocre, and cards that have never seen play in any format can be some of the best. Ninety-nine cards is fewer than you'd think, and when figuring out which cards need to go, these tips can make thinks a lot easier.

Multitask

Some of the best cards in Commander are those that fulfill two different purposes at the same time. Commander games last a long time, and having that extra bit of value can be the key to victory. Most commonly, these cards are creatures that have some additional effect. Indrik Stomphowler, Acidic Slime, and Woodfall Primus are very useful cards to have around, and can take care of many pesky permanents. There are also cards like Deadwood Treefolk and Genesis that can help you get back some of your fallen allies, and creatures like Godo, Bandit Warlord and Taj-Nar Swordsmith can grab a piece of equipment for you. In addition to the many two-for-one creatures, there are also spells that can take care of multiple permanents at once. Cards like Return to Dust and Ashes to Ashes can be extremely useful when there are a lot of dangerous things on the board. Keep an eye out for any card that performs two different functions, and try to make sure your deck has at least a few of these valuable spells.

Size Matters

Huge creatures are an integral part of Commander. When playing with 40 life, and often against multiple opponents, giant beaters are by far the most efficient way to get things done. With so many fatties around, smaller creatures are going to have a hard time accomplishing anything. Unless it also has a very valuable ability, I'd be hesitant to include anything smaller than a 4/4. If it's 3/3 or smaller, it should probably be treated less like a creature with an ability, and more like a spell that happens to give you a free chump-blocker. If it's still good, it might be worth including. Eternal Witness, Yavimaya Elder, and Wood Elves are all small creatures that are still great in Commander due to their abilities. When selecting creatures for your deck, bear in mind that the average size of ground creatures in Commander is around 6/6, while flyers tend to hover near 5/5 or so. Creatures smaller than this can still be valuable if they have a strong ability like Archon of Justice, have the ability to grow bigger like Chameleon Colossus or Figure of Destiny, or are extremely resilient, like Thrun, the Last Troll. Any creature larger than these averages has the potential to be very valuable.

Big Isn't Enough

Despite the importance of creature size in Commander, being big isn't a good enough reason to include a card in your deck. Although they may be well over the average size, you should probably try to stay away from vanilla or French vanilla creatures like Goliath Sphinx or Fusion Elemental. The major exceptions to this are creatures with multiple valuable abilities, especially Shroud, various forms of evasion, and protection. Akroma, Angel of Wrath is one of the most powerful creatures in Commander, simply because the combination of so many great keywords is extremely powerful. In general, though, you'll want almost every creature in your deck to have a powerful ability or two backing it up. Some of the most useful abilities in Commander are those that make the creature harder to kill, like Weatherseed Treefolk, and those that provide additional value even if the creature dies, like Keiga, the Tide Star and Grave Titan. Creatures get killed all the time in Commander, and you should try to make sure that your opponents can't blow you out with a simple Terminate or two.

Mana Is No Object

Between the length of the games and the plethora of great mana-acceleration available, nothing is uncastable in Commander. Even at over 10 mana, cards like Blightsteel Colossus, Darksteel Colossus, and Ulamog, the Infinite Gyre are strong finishers that see play in all sorts of decks. In fact, sometimes the most expensive cards are the best. You'll get a lot more bang for your buck spending 11 mana than you will spending 5. You shouldn't completely fill your deck with expensive spells, but a few big finishers can really help close out a game. Especially when building on a budget, cards that were simply too expensive to see play in Standard can be all-stars. Oft-overlooked creatures like Pit Spawn and Hypnox get a chance to really shine in Commander, and have the ability to singlehandedly take over games. Keep an eye out for underrated fatties like these.

Gifts That Keep on Giving

In case I haven't said this enough, Commander games last a long time. In general, repeatable effects are going to be a lot better than their one-shot counterparts. Given the choice between Honden of Seeing Winds and Tidings, I'd take the Honden almost every time. Need a good Zombify? Maybe Strands of Night will better serve your purposes. Need an Explore? Try Gaea's Touch. If you're looking for something like Back to Nature, Tranquil Grove might be worth including. There are a lot of enchantments, creatures, and artifacts with repeatable effects in Magic, and most of them can be very useful in Commander. It may seem like you're paying a lot for a small effect at first, but these small effects can add up over the turns and eventually help you take over the game. Whenever you find yourself looking for a card to fill a particular function in your deck, make sure to check for cards that will let you perform that function over and over again.

The number or cards available in Commander is simply staggering, and having such an overwhelming selection of playable options can make even the smallest choice difficult. Whether you're building a new deck or overhauling an old one, these concepts can be invaluable in identifying which cards are good enough to make the cut. I hope that sculpting a game-winning machine, breathing new life into an old favorite, or finding the last few utility cards for your theme deck all just got a little easier.