Concentrate on harvesters and refineries in the early game. (To ensure a strong economy.)
To effectively attack early in the game, use long-distance weapons. Make sure you can back up those weapons with anti-air or anti-tank units, and...
Do not waste units. Example: do not attack with one Medium Tank against the enemy. Such an attack will result in both lost production time and money. This will also alert the enemy to build defenses which could be difficult to overcome later in game.
Always make sure the Harvesters (Ore Trucks) go to the closest Ore Refineries, and that they are as close to the ore as possible.
Sell unused buildings such as refineries near empty resource patches.
Use arrow keys for moving the screen and disable scrolling when touching the edges with mouse. This increases control over the screen and player units. (It is recommended to use middle-mouse to pan. This is fast and accurate.)
Play on a large screen at the highest native display resolution. This allows the player to see more of the map at once with minimal scrolling, a clear advantage.
Constantly search for crates, which provide randomized rewards of bonus units, credits, unit or global repair and more.
Always have a defensive building ready to be deployed. This provides some time to fortify the base when attacked by the enemy.