-get your props together ahead of time - ultrasound picture, baby shoes, baby blocks, flowers - whatever you want to use
-wear what makes you feel beautiful. long, flowy tube-style dresses are very nice for showing off that lovely baby shape.
-bring a pair of normal jeans - not the maternity, belly-panel kind
-a button-up shirt makes exposing the belly convenient & simple
-moisturize the belly!
-bring Dad! by having him along, it opens up our photo possibilities enormously - dads make great props! (just make sure they are wearing dark clothing, as the focus should always be on you & that beautiful belly).