Just because a source sounds confident does not mean that it is a quality source. In addition, just because a resource is found in the library does not mean that it is an authoritative voice on the subject or that it is reliable.
When you are finding resources, it is important to look at key aspects of the source to determine if it is a quality source and/or how to use it within a paper or project. It may be helpful to learn this by remembering the acronym, TRAAP.
These are important questions to ask for when you do research.
T - Timeliness
It is important to consider that more recent and updated information may be available about your topic. This could be new research or arguments made regarding your topic. In order to have a well-rounded research paper, you need to have new ways. Older material should not be discounted; however, it should not be the only resources that you cite.
R- Relevance
As you research, you need to determine if your sources address your topic in detail. If your topic is not addressed in detail, then it may not be a resource to spend time with. Also, you need to determine if the source is giving quality information on your topic. Another, thing to determine is if the type of source (book, journal article, magazine, newspaper, etc.) meets the requirement of your professor.
A- Authority
Sometimes, those who write resources do not have the degrees and experience that match their field. It is important to determine who is writing the resource for that reason. It is also important to take a look at the publisher. You should take a look at whether the publisher is well known or from an academic society. It is also important to look at whether the author published the material on their own.
A- Accuracy
If a source does not contain any cited material, then it has not been well researched and would not be of use for your research. It is important for facts and claims made in sources to be verified. If the resource has spelling and grammatical errors then it has not gone through any editing or scrutiny by those who published it. This means that the quality of the work is not reputable.
P-Purpose
You need to determine who your source was written for and if there are any biases. This will help to determine if the narrative is bent towards a certain way. Once you understand if there is a bias, then that can help you determine how to use it in your paper or project.