Answer:
Know site's purpose.
Know the original source of the information on the site.
Step-by-step explanation:
These two aspects are mandatory when consuming information from a health products/services websites, because the original source will ensure the veracity or falseness of the information you are seeing on the site.
Also, it's important to know the purpose of the site, that way you will see if the website offers you what you are looking for. If you are looking some nutritional site, and the purpose is to educate about healthy nutritional habits, then you will be sure that you are gonna get the information you want.
In addition, these aspects are important because on the Internet there are two many websites that offer false information which is not based on scientific researches, which is not good because it's about health, and a misleading information could get you in problems.