Basically for the morphs that are expressed by being homozygous recessive (which is most morphs), a good rule of thumb is that if you want a specific trait in an offspring, both parents should have a recessive copy of that trait. So if you want amel...both parents should be either homozygous recessive (i.e. showing the trait already), or heterozygous (het.) for that trait. If you want snows (amel + anery), then both parents would need to be either homozygous recessive, or heterozygous for both amel and anery.
Etc..etc...