Babies love to be swaddled during their first weeks because swaddling works in part by mimicking the close conditions of the womb. That makes your baby feel warm and secure.
Tummy time helps a baby develop large motor skills. Don't force the issue, but also don't feel you have to spend a lot of time on it to get the benefits. Three to ten minutes twice a day will do.
Peekaboo helps your baby understand object permanence, which lets her know you still exist even when you're not in sight.
A predictable daily routine, is associated with the release of fewer stress hormones, so both you and your baby will be calmer.