When you send something with a courier company, one of the most important parts of your responsibility is to make sure that your packages are always packed correctly. It is the job of your Chicago delivery service to make sure that your package gets safely to its destination. They can't be reasonably expected to do this though if you haven't followed their guidelines as to how to pack your shipment correctly.
The courier is not, and should not be, responsible for having to handle each package with kid gloves to accommodate for poor packing on the behalf of their clients, as this would simply slow the operation down too much. That is why every courier company will have guidelines to help you understand how you need to prepare your package for shipping. If you're unfamiliar with how to pack properly, you should ask your courier for a copy of these guidelines.
The basic idea of any set of guidelines is that you should secure your package in such a way that it can be handled reasonably normally without fear of damage. For instance, if you're shipping anything which is breakable, you need to make sure to fill all empty space in the package. If you fill up a box with bubble wrap or packing peanuts, a little movement won't damage your item at all. If you just set it in a box, there is a good chance of it getting broken.
The next thing that you need to do, when packing something, is make sure that the box is strong enough to support your shipment. Always assume that there is a chance of your package getting damp. If it does, is your box strong enough to support the weight of your item? Also, concerning the fact that your package may become damp, if your item could be damaged by moisture, you should be sure to seal it in plastic or wrap it in something protective.
Some packing guidelines won't have to do with the packing as much as the labeling. Couriers lose a lot of packages because labels are either affixed poorly, or are not clearly marked. A good tip that is included in many packing guidelines is that you should always include an extra copy of the shipping and return address inside the package in case something happens to damage the outside label, that way someone can either still complete the order, or return the package to you.