Never fight a professional army head on. Always use hit and run tactics. Shoot from far, make sure the enemy is distracted and always use the element of surprise. Break the enemys' will to fight. Turn this country into a snipers' paradise. Be weary of drones. They can pick up body heat and see through houses. Small teams. Sabotage of crucial targets, assassination of crucial leadership, acquire supplies by any means. Decentralized command (stay mobile and unpredictable) and compartmentalize information (no one knows everything). Eliminate spies quickly after interrogation.
Study Asymmetric warfare.
Learn: (1)Weapons handling (2)Information collecting by any means (3) Foreign languages