i've found the easiest way is to take the mother to be shopping. let them pick the main fabric, maybe 1 more....and go from there
my dgs baby quilt is midnight blue fabric w/shooting stars thru it (it was a christmas fabric) with sashing in jade green w/small harliquin diamonds. i used baby blue and light purple batiks for the rest.
the day after we went shopping, i went back to the lqs, and got the rest of the bolt of the blue, made the dust ruffle for the crib, the bumper pads ...also made a 24" pillow with the square set on diagonal for watching tv...dgs is almost 3 now, and he carries the pillow & quilt into the sitting room to lay on the floor w/grumpy (my dh) and watch tv...