Once you have identified a topic, spend some time figuring out the keywords. These terms will help you find more resources related to your topic, or may help you find more relevant resources.
For example, try creating a mind map of your research idea:
Keywords you might derive from this mindmap include: star formation rates; Milky Way Galaxy; galaxy evolution; Sun.
You can see, too, that if your search is too broad you might be able to limit your search just to our Sun or observations from a specific group.
There are many ways to figure out what keywords fit best for your research! Concept maps, thesauri, dictionaries, and looking at the keywords provided in an article you're reading can all help you figure out new terms to use in your searches.
Keep a research journal -- this is where you keep notes on search terms you have tried and in what combinations.Write about what's been successful, what's frustrated you, or take notes about what you're reading. It doesn't have to be anything fancy, elaborate, or even academic -- just a way to keep a log of your thoughts and what you've found.
A research journal will help you see what you've tried, what ideas you've had, and can help you discover new connections. If nothing else, it will help make sure you aren't doing the same thing over and over and over again!
From a PhD perspective -- but relevant at any level!
Narrow or Broaden Your Search
Narrowing your search:
Combining your keywords or phrases: Use AND to search for items that contain both phrases you are looking for.
Using AND will give you fewer results, because you are specifically looking for items that have all of the terms you are searching for.
Limit phrases that are not related to your search: Use NOT with a term that keeps popping up that's not relevant to your particular search!
Using NOT will exclude a particular term -- it will give you fewer results, but can exclude relevant results, too, so use this carefully.
Phrase searching: Use quotation marks ("_") around the phrase you'd like to search.
E.g., "black hole", "star formation rate" will return more precise results than a search for star formation rate
Broadening your search:
Add synonyms to your search: Use OR to add common synonyms that can broaden your search.
Using OR will give you more results because you're searching for more than one term.
Truncating search terms: Truncating a term means that a database will search for multiple iterations of a word. To truncate a term, you add a truncation symbol (typically the asterix, *) to the root of a word.
E.g., planet* will give you results for planet, planets, planetoid, planetoids, planetary, etc.