I'd suggest you wear a dress that is cute and nicer than daily wear, but modest. Something that hits slightly above your knee and covers your bra straps. Wear your hair in either a low ponytail with curled ends, or a side braid if it's long enough. If it's shorter, just pin back the sides with plain bobby pins to keep your hair out of your face. Keep your makeup simple, but a notch above what you wear daily. I'd suggest you add 2 things to your daily makeup routine. So, for example, if you normally only wear powder and lip gloss, maybe add mascara and eye-shadow. I'd suggest a light neutral eye-shadow like a peach or champagne color, a thin line of eyeliner in a dark brown (not black), mascara, foundation/tinted moisturizer, light blush, and lip gloss. Have fun!
Don't wear anything super fancy or 'slutty,' but rather something that you would wear to a nice family dinner. I wouldn't go with anything form fitting, but rather something loose. Since you said you had blue eyes, I think that a blue dress would complement them nicely. Hope this helps!
