Mastering controls is paramount. The left mouse button selects units and buildings, while the right mouse button issues commands (move, attack, gather). Double-clicking a unit selects all visible units of that type. Holding Shift while selecting allows you to add or remove units from a selection. Grouping units with Ctrl + Number (1-9) is essential for army management. Pressing the number key then selects that group, and double-tapping it centers your camera on them. 'H' selects your Town Center, 'Q' cycles through idle Villagers, and 'W' cycles through idle military units. These hotkeys save precious seconds during intense battles.
Other vital hotkeys include 'Spacebar' to center on the last event, 'F1' for help, and 'Esc' to open the game menu. Learning to use hotkeys for building structures (e.g., 'A' for Barracks, 'S' for Stable) and training units will dramatically improve your build order execution and overall game speed. Practice these controls in skirmish mode until they become second nature.