Some simple things are Drink more water. Start a low-level exercise program. Eat foods that are high in fiber, like oatmeal, vegetables, and prunes. Try to go to the bathroom after you eat a meal. If these approaches don't work, try taking a fiber supplement.
Fiber supplements are available in many different forms, including pills and powder.
Either way, you should take the supplement with a full glass of water. If you don't take it with enough water, it can make your constipation worse. The synthetic fibers tend to produce less gas. If the fiber supplement doesn't work, talk to your doctor about other treatments. Always consult your own doctor about any opinions or recommendations with respect to your symptoms or medical condition.