I go with what the parents tastes are. I can't really stand many shades of pink but am finishing up one that is primarally pink. almost all my girl quilts have purple in them because its my favorite color. I do like blues and greens for boys though. I try to make quilts that mom will like and be more apt to use. because if mom doesn't like it it won't be used. I find 40" is a really good size to make for the baby to use. if it for the crib then I make it larger to fit a toddler bed.