I know I am guilty of saying cherry shrimp are like guppies in just add water, but for good quality shrimp there is a bit more involved.
For starters buy as high/ good quality shrimp that you can afford, at least then you are starting from a good place. Start off with around 20 and if you get to hand pick the shrimp be sure to get a few males as well as the nice red females.
Feed the cherry shrimp good quality foods, with plenty of variety including defrosted bloodworms at least once a week as well as fresh fruit like bananas, rockmelon. Try to always make sure any fresh fruit or veg that you give your shrimp has been organically grown, to remove the risk of any chemicals entering the tank.
Plant life in the tank is also important for the shrimp, they will spend ours picking through it and the shrimplets have somewhere safe to feed and hide,
Once you start getting maturing shrimplets then you need to be ready to cull/ remove any that are not showing the characteristics that you want, but keep in mind the shrimps colours can change a bit over the course of their development. maturing.
For posting depending on where you are, you may need heat packs in the parcel, or only send the shrimp when mild weather is expected, too hot or too cold is never good for any shrimp. Styrofoam boxes are also good to package the shrimp in as this will help control the waters temp inside the box.I have received shrimp in drink bottles with some plant life for them to cling too and they do fine. Kordon bags are also a great way of sending shrimp, but if the bags are going via airmail then I would double bag them, I have heard of one instance where the bag popped and its suspected from air pressure.