The first thing you should do in most missions is get your SCV fleet working. Immediately get them mining for minerals, building a refinery and gathering vespene gas. If the mission requires lots of building, it's also a good idea to build plenty of extra SCVs (your command center can build them). Build SCVs early to augment your mineral and vespene supplies as quickly as possible. You'll want plenty of SCVs so that you can deploy one or two to build supply depots and such without severely hampering your resource collection.

For most missions, you'll need to build up a sizable force and take that force across the map to fulfill the various goals of the mission. But don't let the main goals distract you from protecting your own base. You should always leave behind a small contingent of units to guard the base, using the patrol command to give them an area to watch over. If the units aren't patrolling, they'll often ignore attacks on your base that are just outside their range of detection.

A medical staff is an important part of any army, but they can't do everything. If your crew consists of only human units like marines, marauders, and reapers, medics are all you'll need for keeping the lot in tip-top shape. However, if you're using vehicle units like hellions, siege tanks, and vikings, be sure to accompany your company with a few SCVs that'll carry out the required repairs.

If you're new to real-time strategy games, this is a difficult skill to pick up but completely vital. Learn to multi-task. Get used to issuing commands and letting your units carry them out without your constant supervision. If you've got an attack crew on the prowl, be sure to issue them commands to keep them busy while you switch back to base to issue building commands. Similarly, while you're overseeing a raid on an enemy base, be sure that your base is kept busy. A lot of StarCraft is getting your ducks in a row and allowing—to some extent, at least—things to play out automatically. Part of this skill includes...

If you do nothing but instruct a barracks, command depot or factory to build units, the complete units will roll out and stand idly by. However, you can make them automatically go to work by selecting the building that's creating the unit and right-clicking on a target. Building SCVs? Select the command center and right-click on the mineral deposits to automatically send completed SCV units to mineral mining. Need more marines in your bunkers or want to add a medic to your patrol? With the barracks selected, right-click on a bunker or a patrolling unit to automatically send trained units to join the fun.

Vital! If you're not already binding groups of units to your number keys (e.g. 1, 2, 3, 4, 5, 6, 7, 8, 9, 0), you need to start. Select a group of units and press SHIFT + 1 to bind them to the 1 key. Whenever you'd like to select that exact same group of units, you can simply press the 1 key. This'll let you quickly and easily order multiple groups of units to carry out different commands. Tell group 1 to attack an enemy base, make group 2 patrol the western entrance of your own base and group 3 patrol the eastern entrance. A single unit can belong to multiple groups, so you can create a big mass of units bound to key 1 but also assign that group's SCVs to key 2 to issue unique orders to the SCVs specifically.

In addition to binding units to numbers, you should also bind frequently-accessed buildings to your keys. Bind your barracks to the 0 key and you can quickly see its progress and issue it new training commands while you're away from base. Say you're currently observing an army you've amassed as it steamrolls an enemy base. Without having to move the camera back to your base, you can press the 0 key to select your barracks and see that it has room in the training queue for more units. Issue the training instructions or change the destination of trained units (by right-clicking with the barracks selected) without having to leave the action.

There are two main commands for moving units around. The basic move command can be executed by simply right-clicking an area with your units selected. The move command send the units to the designated area, but they won't do anything until they get there—if they're attacked on the way, your units will simply ignore their attackers until they reach the destination. The attack command can be used to move your units around, similar to the move command, by simply attack-commanding the units to an area instead of an enemy unit. The difference, however, is that the attack command lets your units stop to defend themselves if they get attacked.

Want to issue a series of commands to the same unit or group of units? You should. Queuing up commands is new to StarCraft 2 and lets you do things like, say, order an SCV to build five supply depots before returning to work mining for minerals. Simply hold the SHIFT key while issuing commands and the commands will be carried out in the order you issue them. You can also use this to move your units along a personally-chosen path to a destination by holding SHIFT and right-clicking the path you want, rather than allowing the units to find their own path to the destination.

Above all else, in StarCraft 2 you need to be fast and efficient. To issue commands with the utmost quickness, you'll want to learn a handful of keyboard shortcuts, or hotkeys. Hotkeys allow you to replace time-sucking menu selections with quick key presses. Memorizing the hotkeys on the following page will surely boost your APM (actions per minute).