Newer Magic: The Gathering players have much more to learn than just the basic rules. The trading card game has a lot of different strategic layers, and card advantage is one of the most important.
Magic has three resource systems: mana, life points and cards. Mana and life points are pretty obvious to all players, but card advantage isn't as clear, despite the fact nothing is possible in Magic without cards. Any deck can harness the power of card advantage, but the ways to do so are not always apparent. Let's dive into the world of card advantage.
Resource Attrition
Card advantage is often how Magic players get ahead in games of attrition, and this is especially true for mid-range and control decks, which don't aim to win by turn four via aggro or combos. In short, card advantage means keeping pace or getting ahead while spending fewer cards than your opponent. Someone who gets ahead in card advantage will have more cards in their hand than their opponent, and might stay that way until they win. Card advantage doesn't guarantee victory, but it can go a long way. A player who keeps pace with five to seven cards in their hand going against someone who has to immediately use every card they draw just to stay alive has a clear advantage..
Generating Card Advantage
A player can generate card advantage with one or both of the following methods: Drawing more cards than the opponent, or making the opponent spend more cards than them to keep up. Blue mana excels at the former, and Red and Black excel at the latter.
Some cards have a cantrip ability, meaning they have their own effects and then allow the caster to draw a card. These cards replace themselves, negating the inherent "you lose one card from your hand" cost of using that card. Players must spend cards to be active in the game, and they can dodge that -1 card cost with cantrips. But that's just the start.
Players can further avoid the -1 card cost in a variety of ways. They can cast spells or use abilities that create many more cards for them, such as Divination, Painful Truths, Ancestral Visions and Sphinx's Revelation to draw many cards at once. Casting Sphinx's Revelation is -1 on its own, but should you draw four cards with it, your card advantage becomes +3. Ordinarily, having +0 card advantage is solid, so +3 is downright incredible. Some activated abilities can draw cards on that scale, too.
That's not the only option. Players can destroy multiple cards their opponents has with certain effects, such as board wipes (Damnation, Supreme Verdict, etc). If you have one creature and your opponent has five, you can cast Damnation to reset an unfavorable board state and gain card advantage. Casting Damnation is -1 on its own, and there's another -1 for your lost creature. But you generate +5 for the opposing creatures you wiped out, so the math works out to +3 card advantage. "Two-for-one" spells can do something similar on a smaller scale, such as Electrolyze dealing 1 point of damage to two opposing creatures with 1 toughness each. Electrolyze also cantrips, meaning it generates +2 card advantage in this case.
You can also cast a creature, planeswalker or another permanent that the opponent has to use more than one card to defeat. If you keep attacking with a massive creature and your opponent sacrifices multiple blockers to it, you have generated card advantage. Or, your creature makes a creature token (such as Thragtusk) and your opponent loses multiple cards to deal with both. Creating creature tokens is known as "virtual card advantage" and can be quite helpful, especially if you just spend one card to make 2+ tokens.
Finally, don't forget flashback effects, such as on Think Twice or Lingering Souls. You effectively cast the card twice, but only have -1 card advantage instead of -2. Snapcaster Mage and Past in Flames can give any instant or sorcery in your graveyard flashback, too.