Do not seek out combat with government patrols until you have stocked up on long-range weapons. Also, any group of more than four or five enemy soldiers will split up and flank your position, so prepare your own ambush.
Don't forget--to get a mine to produce money for you, you must find the mine foreman and make him happy. Seizing the town the mine is in is not enough.
Your first priority is to establish a financial base--seize the first mine at Drassen as soon as possible. To this end, it is worth your money to blow $10,000 to $15,000 on a top-of-the-line mercenary on a one-day contract. Choose someone with a long-range rifle and excellent marksmanship. Remember, you get to keep his equipment at the end of the day.