It happens every year. The calendar flips to January, and we immediately resolve to lose weight, eat right and exercise more. Setting the goal is the easy part — getting that resolution to last more than a week or two is the real challenge. This year, resolve to get healthier and happier one day at a time. Here are 31 simple, specific tips (one for every day of the month!) that will get you into the habit of living healthier all year long.