Be prepared for the growth (and crying) spurts.
Roll up your sleeves because things are about to get messier, dirtier and fussier. Most babies experience a growth spurt after 10 days of birth. This will likely coincide with an increase in appetite aka diaper changes. Expect frequent feeding and cleaning sessions.
In addition to weight, your baby will also gain muscle control. This means they will (hopefully) be able to focus on objects 8 to 14 inches away--just about the distance between his eyes and yours during feedings.
On the downside, this new phase will also bring out the fussiness. Expect them to cry (a lot). Coping with colicky babies is tough so keep your calm and try to soothe them with your voice and environmental factors.
Don't be afraid of spoiling your baby by picking him/her up when he/she cries — but don't feel guilty about letting them cry for a few minutes either.