Successful vendors take precautions to stay anonymous; then exercise them at all cost.
Keep up with up to date with your shipping stealth and options, e.g. use Moisture Barrier Bags. Constantly try to change your methods and avoid making patterns in your business, e.g. same drop location and times, same packaging.
Some things to be aware of that can be used against you.
If your stealth methods require you to use a printer, know that investigators can and will decode your prints to identify your printer type, brand and model if they get a hold of one of your packages. The same goes for your hand writing.
Keep your work area sanitized and take care when packaging your items. Avoid using tape, and properly wipe your packages from residual, preferably with ethanol. DNA material such as dead skin and loose hair may also find its way onto your packages. We recommend vendors to store and pack your items in separate rooms.
If you have generated or opened your bitcoin wallets outside a virtualbox, consider your wallets forever exposed. Your wallet keys are now secretly storing your real IP adddress. If you intend to cash out or use your wallets illegally, start over and always remember to run your wallets through tor, e.g. simply route your bitcoin client through the tor proxy before connecting to the internet. Otherwise, use Whonix or software of similar nature to shield your identity.
Tor is open-source software. Keep up with new updates and make sure to download and verify the latest tor bundle when it gets released. You may also consider using VPN, if you wish for an extra layer of security.