Aww man. I remember this vividly. Around one month old, i started to expose baby to sunlight, just hanging by the windows to see outside, so not direct sunlight. Helps with melatonin production which puts baby to sleep at the right times in the evening. Constantly did this for a couple weeks and she slowly shifted to sleeping from eleven pm, then down to ten then now at seven months around 8pm ish.
Tania