With typical equity investing, potential returns are asymmetric. That is, the downside is limited as the most an investor can potentially lose is the amount they have invested. As for upside potential, an investor can potentially earn many times their investment as a company grows. Over time, in some cases this could be 3x, 5x, even 10x the original investment. A few good investments can more than offset mediocre and bad returns in the rest of the portfolio. Colloquially these investments are termed multi-baggers (ie. Five-bagger, Ten-bagger).
By comparison, gambling is asymmetric as well, however the odds are designed by the house to be in their favour, not yours. That is, the frequency of hitting the jackpot is very low. Gambling is also zero sum, in that what the house wins, you lose. Unlike gambling, equity investing has a positive bias over time from growth of the company and profit growth.
The number of good investment ideas you have tends to be proportional to the number of companies you have researched. For example, of ten companies you may look at, it may be that only one of them is good. You have to turn over a lot of rocks before you will find something exceptional. An investor can be selective by only investing in the best prospects and avoid investing in mediocre ideas. For example, an investor may choose 20 companies out of 200.
You can have an edge from investing in a company who's business you already understand and whose products you use. Depending on the product or service, as a consumer you may already have an intimate understanding of the product quality, the competitive landscape, demand, the value proposition, who is buying, flaws, and the popularity of a product.
Consumer knowledge is often given less credit than it deserves. Lynch gives the example that some of his best investment ideas came from asking his wife and children about products they were using.
Good investing is equal parts art, legwork, and science. Often not enough attention is given to legwork. For example, a potential place to look for ideas is the mall - you can see first hand how popular the business is and how the business sells to consumers. This is as opposed to getting the information second hand through reports, which may be slow to catch on to growing companies and trends. However this should complement, not replace, a detailed financial and company analysis.
Good business models tend to be scalable. That is, the success of the business can be replicated and the number of stores can increase by entering new locations or markets. The revenue generated by the company can grow exponentially. Furthermore, average costs may decline as the burden is shared over a larger network.