You only start off with one available lieutenant slot in this game, but by completing more and more jobs, you will unlock more and more slots for lieutenants, for free. Know the difference between invading and dueling before you decide to battle. Starting a war against another gangster will pit all of your gangsters, weapons and armor against all of their gangsters, weapons and armor. Each member of your gang can equip one weapon, one gear, and one vehicle to increase their attack and their defense, so buy one of each for each lieutenant that you have. Vehicles are expensive, but they are important for battle, too, and since often people are going to neglect buying vehicles due to how much they cost, you can gain an instant advantage by including them in your purchases. Send gifts to your allies and they will be prompted to send you gifts back. Participate in the boss fights as often as possible, because they are an excellent way to increase your experience and level up when you run out of energy.