Item Number 7 (Hint: Read It)
I don't recommend investing in indvidual stocks if you're crunched for time, however, if you are not going to read the entire 10-K of a company and it's competitors before investing, you should at least read item number 7.
Item Number 7 on the 10-K is probably the most important section. This is where the management team discusses company results and financial conditions. You can pick up some amazing insights into companies past performance and how the management team thinks the company will perform in the future.
The reality is than not even 20% (I'm being generous) of the people who invest in individual stocks read a 10K and it's a pretty significant edge for those who do. It's the best place to find red flags!