Make policies, measure the polls, and try to maintain over 50% of the vote each election.
You'll need to be very careful - policies which may be immediately popular with the voters may also lead your country into long-term ruin. Analyze data, review reports and make decisions that will affect your country and possibly your popularity.
Free Health Care? You bet! But when you have to raise taxes to pay for it... See how long you can stay in power!