It is recommended that you use the game tutorials, as they are essential to completing the game and provide fundamental knowledge and understanding of the game's workings. However, the final tutorial (Air Force Training) is very difficult. There is no set way to complete it, except by outsmarting the CPU. The best advice is to keep all of your Anti-Aircraft Cannons alive above all other vehicles and units.
While playing the game, save the game then open up the menu and select "Surrender". The general will tell you a new strategy. Then, just load or restart your game.
Take a truck or scout near a tank or rocket launcher. Move it around the screen until you find the unit, then take it out with the tank or rocket launcher.