Just like field research, library research is not a linear process. It is a matter of trying, evaluating and learning from the results, trying again with your newly-gained knowledge, and exploring possibilities. Unlike field research, there's a lot less hitting things with rock hammers. Even so, it can be fun and exciting to find new information, explore new directions, and think about what all of that might mean for your topic.
Here are a few questions you should ask yourself as you approach the geologic literature. The answers can help you to narrow down the types of sources you look for and the places you search.
Do you need geographically specific information, or is the locale not important? For example, water quality data is location-specific, but articles about minerals containing europium need not be.
Are you looking for information on a specific resource or material, be it a specific type of rock, or mineral or even energy resource?
Do you need information on a specific process or cycle?
Does your information need to be time-specific? Are you looking for information from a particular geologic time period?
Once you've defined what you're looking for in a source, it's time to do the actual searching.
If there are any aspects of your topic that you don't have a good handle on yet, it's going to be worth your time to do some quick background reading. Find a 1-2 page summary of the topic to give you some context, which will help you understand the research you find later on. The "Finding Background Information" tab on this guide will give you some links to places to find background information.
I like to start my search in either CLICsearch (for a broader search) or GeoRef (if I want to a narrower, geology-focused search). I try a few of the key words or phrases I've identified above and look at the results. Don't get too caught up in finding the perfect search terms, just try some things, see what you get, and be willing to try something else. Pay attention to the ways that you can limit a search once it's done. You can narrow results by source type (is it peer-reviewed? an article? a book?), or by date published, or subject. These are easy ways to comb through results.
Use the tabs along the top of this guide to help you find different types of sources.
Once you've found even just one good source, you can use that to find more sources.
While skimming through a source, pay attention to the terms or phrases that the author is using to describe your topic. Make note of any key phrases that you might add to your search.
Other things to watch for:
Pay attention to things like author names and affiliations. While it's not a problem to have a few sources written by the same author, you want to avoid having all your sources written by the same person or coming from the same lab. You want to be sure you're bringing in multiple perspectives and voices.