StarCraft: The Opening

In StarCraft, an opening is the first couple (roughly two) minutes of the game in which every player has the same goal: build an economy. Each race opening is generally the same, as there are only a select few methods of effective beginnings to the game. Past this time period, each opening diverges into many different builds in which will decide the events of the “early game.”

Standard Terran opening:

Supply Count Instruction
4/10 SCV
5/10 SCV
6/10 SCV
7/10 SCV
8/10 SCV, Supply Depot, scout1
9/10 SCV
10/18 SCV, Barracks2

Standard Protoss opening:

Psi Count Instruction
4/9 Probe
5/9 Probe
6/9 Probe
7/9 Probe, Pylon, scout1
8/9 Probe
9/17 Probe
10/17 Probe, Gateway

Standard Zerg opening:

Control Count Instruction
4/8 Drone, scout3
5/8 Drone
6/8 Drone
7/8 Drone, Overlord3
8/8 Drone
9/17 Drone
10/17 Drone4

Tip: See the Cloning article for information on how to manage your first 4 peons.
Notes:

1 Scout with 1 SCV/Probe to the position closest to you. Harass the player with your peon.

Tip: See the Harrassment article for further concepts. Harassment is mentioned in this article because it may occur as early as the 2-minute mark. I also like segways...

2 Create the Barracks with the SCV that finished the Supply Depot.
3 Send your Overlord to the closest position near you. When you scout with your Drone, scout to the next closest position. If you have found the player with your Overlord, harass with your Drone.
4 Continue to construct Drones. While doing so, allow excess minerals to accumulate. When the mineral count is near 300, send a Drone to your Natural Expansion to construct a Hatchery. (This may vary depending on situation. The general concept is to build a second Hatchery within the first minutes of the game.)

General Tips:

As a general rule, build peons for the first seven minutes.