In order to find undervalued stocks, first you should develop a list of stocks you want to analyse depending on your basic criterias, secondly analyse financial datas from each of these stocks and perform a more in-depth analysis.
It is now easier than before to find financial datas on the internet with website such as bloomberg, yahoo finance and on the website of the company itself where they usually have the yearly and quaterly financial reports for the past years. Many financial websites will provide you informations such as stock price, earning per share P/E ratios and so on.
Benjamin Graham once said that to consider a stock undervalued, its stock price must be at least 1/3 below its intrinsic value, here are some basic assumptions that will help you to determine if a stock is undervalued.
Some of the basics of Value Investing: