A common and effective strategy is to storm into an opponent's base and attack the workers harvesting minerals and gas. All three factions can build defensive buildings designed to protect your turf.  Terran: Select an SCV, click Build, then choose Bunker. Bunkers can house up to four combat units, who can fire at approaching units safe and sound from within the Bunker. Train four Marines, then place them in the Bunker by selecting them and right-clicking the Bunker. Protoss: Select a Probe, click Build, then choose Photon Cannon. Photon Cannons fire automatically when enemy units draw near. Remember to place Photon Cannons within a pylon's power field. Zerg: Select a Drone, click Build, then choose Spine Crawler. Spine Crawlers automatically attack enemy units. Remember that Spine Crawlers must be placed on your creep. If you don't find your opponents, they'll find you. Beat them to the punch by sending one or two workers around the map as scouts. Don't worry if they get killed in the line of duty; as long as they find a base, they've done their job. Select a group of combat units by clicking and dragging your cursor over them. Now hold Ctrl and press 1-9 on your keyboard. That entire group will be assigned to the number you select. To control all of them at once, press the number you assigned, then right-click on the ground to move the entire group. Every time you train a new unit or construct a new building, click it and study the abilities and options available to you, highlighted in a box in the lower-right corner of the screen. Grayed-out abilities cannot be used or purchase yet. Hover your cursor over them to learn the prerequisites they require for you to use them. Mineral patches and Vespene geysers will run dry eventually. Gather a retinue of combat units and two or three workers and head to an expansion bay, an area on the map with unclaimed minerals and geysers. Upon your arrival, get your base up and running as quickly as possible.  Assign one of your workers to build a new town hall. Place the...

TL;DR in Indonesian:
Buatlah pertahanan untuk melindungi basis Anda. Intai peta untuk menemukan basis musuh. Kelompokkan unit tempur memakai hotkey. Pelajari unit dan bangunan untuk memahami kemampuannya. Bangunlah basis baru untuk meningkatkan sumber daya Anda. Perluas area sesering mungkin. Terus-menerus belanjakan uang.