Searching for "tea" brings up a variety of articles related to tea taxation, the Boston Tea party, and many others. As you're searching, consider what other words you can add to focus your search. Consider:
tea trade
tea AND (manners OR customs OR etiquette)
tea AND culture
tea consumption
tea AND sugar
tea AND porcelain
These are just a few ideas to get you started. As you search, pay attention to the words that the authors or the database are using to describe the concept that you are interested in, and use those to guide your search.
Use the background sources here, as well as other sources you might encounter, to gather information about your topic and consider what you still need to know before you start researching. You can use this information in searching for primary sources.
- Dates - Places - Names of persons involved - Names of organizations, government agencies, etc. - Names of particular laws or events
Background sources can also help you understand the larger historical context, so that you can determine what primary sources might be most useful or how a particular primary source fits into what was happening at that time.
These are just a few of the reference sources you might use to begin your search. Search Primo, ZSR's Discovery Catalog, for additional titles.
Encyclopedia of World Trade: from Ancient Times to the Present by 
A Companion to Colonial America by 
Europe, 1789-1914: Encyclopedia of the Age of Industry and Empire by 