So I am an excel lover, and I put the basic information for each article into an excel spreadsheet (citation, method, results, overall point, keywords, sometimes notes to myself). This way I can sort based on topic, or results and you can see what you have. It also helps in seeing where you have gaps. I always do this before any writing because it helps me in determining how to organize the actual paper. So you might be passed this point. But hey, if you have time and feel like it give a go I have found it incredibly helpful. Also, my friend did this for her entire dissertation literature over the course of about 3 months, then she was able to write her proposal in a week because everything was already laid out for her!!