Hi there and welcome to the board!
I have to be quick as my little one is waking up.. and my older one is wanting my attention!
Swaddle, block out visual stimulation, pat-shush (with Brendan it was more shush than patting), keeping an eye out for sleep window and ensuring to act on first sleepy cue, decreasing awake time if overtiredness is occuring, keeping activity level low-- overstimulation makes it so hard to fall asleep.
I'll add if I can think of more later!