Today we'll take a closer look at the Aggro archetype, which was previously described as "a strategy that aims to win by producing maximum damage output in the shortest number of turns." In terms of damage, it can be useful to have a baseline by which to compare each of your cards before including them in your deck. I believe Lightning Bolt is one of the best cards to look at here, as its cheap cost and 3 damage output is generally heralded as the most efficient burn spell in Magic. Of course, Lightning Bolt is not currently in Standard and its replacements, Shock and Incinerate, are noticeably less effective at what they do. But this is what we'll be aiming to do with creatures in our Aggro deck. We're trying to convert each spell into maximum damage output, treating our small creatures as basically walking Lightning Bolts or, at the very least, Shocks.
Let's start with some basic first turn creatures. Red's Goblins tend to make for great fodder in an Aggro deck. They can sometimes come in very efficient packages. Look at Goblin Guide, for example, which was the go-to card for Red Aggro with Zendikar Block. He's a 2/2 with Haste for 1 mana! At worst, this guy is a Shock, and he'll often get in for at least 4 before trading with an early blocker, making him more efficient than a Lightning Bolt. White has access to Elite Vanguard, which is the new Savannah Lions. White Weenie(WW) decks often love this high-powered 1-drop. While he's not as powerful as Goblin Guide, he can definitely get in for decent damage early in the game, though he's weak to 1-power defenders. Blue has Phantasmal Bear, a 2/2 for 1 mana with an aversion to being targeted. Finally, check out Memnite! He's a 1/1 for 0 mana! He works especially well on first turn with something like Glint Hawk or Kuldotha Rebirth, either of which lets you get in for 3 damage on Turn 2!
Those are some solid basics, but we should be sure to keep card potential in mind. While a 2/1 for 1 mana is good, you might see more potential in other cards such as Champion of the Parish or Stromkirk Noble. Champion of the Parish is great in a Human-based deck. First turn Champion followed by 2 Humans in the second turn means you're still swinging for 3 second turn, and he's backed up by a 3 toughness making him much harder to kill with early game blockers. Stromkirk Noble, similarly, is amazing if left unchecked. Each turn he gets bigger, as long as he's hitting the opponent, so his potential is huge. He can win a game by himself in only 6 turns if they can't stop him! Blue's got Delver of Secrets which, in the right deck, can be a 3/2 Flier on turn 2. It doesn't have quite the same potential as Stromkirk or Champion, but it's very efficient for Blue(or any color, really) with very little downside. Of course, as the game goes longer, the more answers an opponent is likely to have for your threats, which means that the 3 damage from Champion or Delver on turn 2 can be very important, as opposed to the unrealized potential of a Stromkirk, who only deals 1 damage on turn 2.
Now what about the high-end of your mana curve? What makes a card worth including in an Aggro deck when it costs more than 1? How much can it cost before it stops being worth it? On the whole, Aggro will keep the high-end of the mana curve down to 3 or 4, meaning that the highest costing spell in the deck will have CMC (Converted Mana Cost) of 3 or 4, depending on the build. A Goblin-based Red Aggro deck, for example, may max out their curve with Goblin Chieftain. Having Haste and giving other Goblins +1/+1 and Haste for 3 mana can be a pretty sweet deal. With 3 other vanilla 1/1 goblins in play, dropping him on turn 3 means you're swinging for 8 damage! Hero of Oxid Ridge is another excellent choice for Red at 4 mana, giving an Evasion ability to your creatures and pumping them up with Battle cry!