Swaddle, swaddle, swaddle!
Never put the baby down flat, always elevate the head.
Hold the baby stomach down on your arm, head resting in your hand, legs straddling your arm. The pressure of the belly against the arm helps.
My niece was told to get an exercise ball, or a hoppy ball and sit on it and bounce up and down, that helped as well.
Try the gas drops. Trying changing your diet if you nurse, or the formula if you are bottle feeding.
Check the babie’s ears for fluid.
Try using a swing and a white noise machine for soothing sounds.