I agree with Warren to keep it simple and not use higher mathematics in your analysis.
Be careful of leverage. It can go against you.
One of the tricks of this business is, keep your losses down.
Be aware of the level of the stock market. Are yields low and PE ratios high?
Use book value as a starting point to try and establish the value of the enterprise.
I'm a passive investor. There are people who are very aggressive; they try to buy companies.