Since no one has really answered your question, I will chime in.
Firstly, investing is a very personal thing. The style of investing you follow will depend very much on your temperament, investment timeframe, investable cash flow, time you are willing to commit, etc. Basically, you need an investment philosophy. I don't know any shortcuts for this besides reading a ton of investment books. You can try Damodaran's Investment Philosophy course lectures on YouTube. He'll give an overview of the main investment flavors.
Here's my "process":
- I get ideas by reading a lot: Barron's, WSJ, Fortune, as well as looking at various screeners such as low P/E stocks and companies trading at their 52-week lows. I am skeptical of large cap stocks in the billions, as those are picked over fairly well. Large funds have too much money they need to put to work to invest in a $250MM company, so analysts don't follow them much. These are prime candidates for gaining an edge.
- Then I pull their annual (and quarterly) reports. The AR will give you a feel for the business, how it makes money, growth strategy, etc. A lot of times I don't feel comfortable with my level of understanding and just bail. Sometimes I'm uncomfortable but keep reading for educational purposes, but in the back of my mind I've already firmly placed this in the "pass" category. I also start looking at the industry as a whole and competitors. I start to formulate an opinion on where the business is in general and what the key variables are. Again, the default here is to pass.
- Once I have a feel for the business, I start looking at the numbers, very roughly. Growth, margins, ROC, debt levels, and similar tell the truth about how good of a business this is. I especially look at how these numbers change over time. I look at free cash flow (FCF), but always in tandem with the companies reinvestment needs. More companies go in the "pass" bin during this stage for various reasons, e.g., high ratio of debt to FCF, where one hiccup and they're toast.
- At this point I have a good business with what looks like good numbers, but I need to know a) can I get it for a good price, and b) why?
I figure out what I think is a fair value for the entire business at current conservative levels. I use DCF (you could use multiples I suppose), but I am purposely fuzzy on the numbers, e.g., I round a lot as a constant reminder that I do not know the future! I also play with the inputs (engineers might call it sensitivity analysis) to get a rough range of a fair value.
- I can then see what it's actually trading for. This is why many of my initial filters look for 52-week low stocks and the like, cause otherwise you'll spend a lot of time getting here just to see it's trading for 2x what you think is a fair value.
- The 2nd half of the question, is why is this trading at what I think is a discount? The best candidate company is currently unloved for some reason. Your job is to figure out why.
- Now you are at a point where experience matters, and why Buffet tells his fans to read, read, read. Whatever reason this stock is currently depressed; is it temporary or permanent? If it's temporary, will the company survive (even if things get worse)? You need some kind of edge or insight here, and your general business experience will guide your thinking.
I try to evaluate all possible outcomes and what my annual return will be in each case, and am looking for a margin of safety. Basically, even if things stay bad, will I end up ok? Your best luck here is some kind of safety net to prop up the value close to where you get in, like liquidation value (but be careful here). Think like a business-person.
More often than not, I have no special insight into the current environment and I pass. Every now and then, though, the market gets it wrong. This is your fat pitch and this is the time to swing.
- To keep this somewhat brief, I'll just say there is a ton of nuance, so read books to get more ideas on what to look for. Also know what you're looking at: analyzing Collector's Universe (CLCT, $160MM cap) is different than analyzing Disney, with different investment timeframes, so certain things matter more than others. And both of these are different than looking at a net-net (what Buffet calls a cigar butt, or Graham-style stock).
As the above suggests, not many companies make it all the way through, and that's ok. I read an interview with Mohnish Pabrai recently, and he said something very smart. He said the investor should act like a lady / gentlemen of leisure, casually reading each and every day, keeping an eye out for opportunity, but without the constant impulse to act.
As a beginner, you can even tell yourself as you begin reading that you are not investing, you are just learning. Keep investing in index funds while you learn. You may surprised when a juicy one comes your way.
As for reading, someone else gave some good recs, and you're already reading Graham, so if you've decided "value investing" is for you, I would recommend
- Common Stocks and Uncommon Profits - Fisher. The "scuttlebutt" method for finding good companies. This is good advice in general for learning more about industries.
- One Up on Wall Street - Lynch. High level advice, but good stuff.
If these 2 and TII are a chore for you, then (value) investing is probably not for you. If you like them, then try these:
- Investment Valuation - Aswath Damodaran. The grandaddy of technical valuation. Basically the textbook on doing DCF. Personally I don't obsess over the numbers at this level of detail, but you should learn it. (If a situation is close enough where an 8% discount rate vs. 9% will make the difference between go / no-go, then I am a no-go).
- The Dhando Investor - Mohnish Pabrai. His analysis of Patel's is kinda goofy, but the last half of the book is excellent, and probably the most straightforward advice I've seen for smaller portfolio value investors. He counterbalances the common thought of looking for those 20+ year stocks with his 2-3 year investment method.
- A good Accounting book if you don't already know this stuff.
- Money Masters of our Time - John Train. This will expose you to a lot of different "master" investors with different styles.
This is already too long, and scatter-brained, but I could go on all day about this stuff. If you enjoy the process there's really nothing like it; it's like treasure hunting!