What can be done to make 3 month old baby sleep more longer and comfortable?

At a consistent bed-: time, feed the baby, then wipe out her mouth with a soft cloth. In low light, read to her, cuddle, the put her to bed on her back in her crib in her own room, when she is drowsy, but awake. Allow her to self-calm to sleep without bottle or pacifier to consolidate sleep by 4 -5 mos. & avoid night-waking problems at 5-6 mos., as she'll go back to sleep on her own.