Anytime you have to design a label, you must do it with both the product and the container in mind, otherwise you risk to come up with inadequate designs that will fail to accomplish their purpose.
Additionally, when it comes to label printing, there are some other design conventions that you should know about to ensure the quality of the label, you also want to think about making them peel back labels to provide more product information on your label.
Make sure your label is designed in CMYK, not RGB
CMYK is a four color process. Cyan, magenta, yellow and black are mixed to create any other color. On the other hand, RGB is a three color process (the base colors are red, green, blue) and most of design applications have this mode set by default. Change it, because RGB mode is good for designs intended to be used on electronic screens, while CMYK is better for commercial labels used in real life.
Use Adobe Illustrator instead of other programs
Labels can also be designed in Microsoft Word, but this would be a poor choice for such a task, because the program is not suitable for professional hi-quality label designs. It uses RGB color process, which most commercial label presses do not support, so the design will have to be reworked before printing, which involves extra money. Photoshop is a better choice than Word, but Adobe Illustrator is the best for such a task.