When taking notes from different sources, there are a couple different things that work best for me.

Whether I’m taking notes on index cards or on paper, I always start with the bibliographic information at the top. Under the bibliographic information, the next thing I write is a general idea or summary of what the source is about or the important point it is getting accross. After that, I include any helpful quotes and page numbers that I believe will be useful in my paper. Also, when taking notes, I like to use a hanging indent a lot. I start out writting about a particular idea or subtopic and all of the relevant information after that I indent. It seperates the different ideas without having a heading, which is useful for an early stage of notetaking when I may not know specifically what I’m looking for.
After I have finished taking notes, I tend to organize my sources by argument. I categorize them by what I’m getting out of each source and where in the paper I think it will be relevant instead of organizing them by author or dates of publication.
These are just a few of things that I tend to do when I am taking notes. If anyone has any more suggestions or something that may be more efficient then feel free to comment!