I don't regularly ship them but I know how to. I will try to make the steps as clear as possible.
1. Get some good quality shrimp and cull them.
Once they are in the tank, you will need to cull them. This means that you will need to remove the shrimp with bad colors, so that they are not in the mix for breeding. You can feed the culled shrimp to fish, or move them to another tank. You should always cull them to keep the highest quality possible.
2. Get some high quality food.
One of the most important ingredient in a shrimp's diet is spirulina algae. I chose Fluval Shrimp Granules. It contains a lot of dried spirulina and phosphate. It is also good to have different food options for them. They are scavengers, so they will eat almost anything.
3. Prepare the tank for baby shrimp
Put a sponge or pantyhose over the filter intake to prevent shrimplets from being sucked in. Provide lots of hiding places, such as java moss and other plants.
4. List them for sale
List the shrimp for sale. A good price is $1 each for adults and $.50 each for juveniles. Make sure to provide a picture of the shrimp you are going to sell, because no one likes to receive shrimp that are not as bright as what they were expecting. It also comforts buyers to know exactly what quality they are receiving. Be sure to say what your preferred payment method is. Most people (including myself) use Paypal. You could also accept checks mailed to you. List a DOA policy. I recommend covering DOAs for things like heat pack failures, or just random causes, but not covering things that you can't control like delays in shipping or the package going to the wrong place. Most people only cover the cost of the shrimp/fish if a DOA occurs, because they can't control shipping.
5. Ship them
I'm not going to go into much detail on this one, because shipping shrimp is just like shipping fish. This should help: Shipping Fish and Invertebrates
Make sure there is enough air in the bag. RCS are especially sensitive to co2
. If you keep it at 1/4 water and 3/4 air in the bag, you will be fine. Put something inside the bag with them, so they have something to hold on to. You can use yarn, java moss, anacharis, and lots of other plants.
I hope that helped!