Receiving Silk Road packages discretely:
1. Set up a reliable mailing address.  No mail with your name on it, where you have to pick up and receive from a clerk.  Friend's house is best.  Avoid anyone in this transaction who you don't want knowing about what's inside the package
2. Upon receiving the package, do not sign for it, do not receive it or have your friend receive it directly from a postman.
3. Most packages can be fit into a mailbox.  Consider it suspicious if you order in the quantity of grams and end up with a package conspicuously delivered to you personally or left on your porch.
4. Be aware of any package that looks like it has been opened.