Keeping track of your research will make things a lot easier in the long run. Figure out a way that works for you, maybe a notebook, maybe an online document, perhaps sending emails to a particular folder - something that makes sense to you.
Things to track:
Building a bank of keywords will make the rest of your research much simpler.
1. Gather background information, which will give you some key words to start with, and make your research a little easier.
2. Brainstorm other search terms: think of synonyms, or more technical terms, or official language vs. colloquial language
3. Think of some narrower search terms to get even more specific and some broader words in case you aren't finding much.
4. Think about what ideas and terms are related to your subject that might also be helpful.
Even when you've got a good keyword bank started, keep adding to it!
If you find a good article or book, look at the data record to see what other terms and subjects are used to describe it.
Remember that with library resources especially, it pays to search smart:
use AND in between search terms to group them together
use OR for more results
use NOT if you want to exempt a word from your results
use quotation marks "_" to isolate phrases
use the wildcard * to get all versions of a word