Because all packages are treated differently based on their size and contents, there is no uniform set of rules for shipping a package. However, there are some general guidelines that you can follow when shipping a package to ensure that you safely and securely pack it, purchase the right type of postage for it, and get it where it needs to go promptly. 

Think About What You're Shipping
First of all, you should be aware that there are some items that are prohibited from shipping via standard mail. For example, the United States Postal Service will not accept packages that contain potentially hazardous materials; this includes lithium batteries, paint, chemicals, and potential explosives. Be sure to check with your shipment carrier before you ship to ensure that what you want to send is permitted. Otherwise, you could end up facing hefty fines down the road.

On the other hand, if you are shipping any type of media such as a book, CD, DVD, or anything in between, you should be aware that you could qualify for a media rate of postage. This is a discounted rate that can easily save you 50% or more on your overall shipping costs; just be sure to indicate that the package is being shipped via media mail to the carrier.

Weigh Your Package
If you have a scale available to you, it is a good idea to weigh a package before going to the post office. This way, you can get an idea as to how large the package is and thus how much it is going to cost you to ship. Furthermore, if you are aware of the package weight ahead of time, you can even purchase your postage online rather than having to do so at the post office. Just be sure to weigh at least twice to ensure accuracy.

Pack it Properly
To ensure that your package arrives at its destination intact, you may want to consider purchasing some kind of insurance on it. Often times, this costs just a small amount extra and will protect the items within the shipment up to a certain dollar amount. Furthermore, taking the time to properly pack the box with bubble wrap, Styrofoam, foam peanuts, and other protective supplies is important, especially if you are shipping something that is fragile or easily breakable.

Overall, shipping a package does not have to be rocket science. However, to ensure the best results, it will take you a little bit of planning and research. From there, you can properly pack your items and have them shipped properly in a way that is affordable for you so that they can arrive safely at their destination.