Investors who focus on growth try to predict which companies will grow faster in the future -- faster than the rest of the stocks in the market, or faster than other stocks in the same industry. If you're successful in buying a company that does grow faster than other companies, then it's likely that the price of that company's stock will increase as well, and you can make a profit.
The stock of a company that grows its earnings and revenues faster than average is known as a growth stock. These companies usually pay few or no dividends, since they prefer to reinvest their profits in their business.
Peter Lynch primarily used a growth stock approach in managing the Magellan mutual fund. Individuals who invest in growth stocks often prefer it because their portfolio will be made up of established, well-managed companies that can be held onto for many years. Companies like Coca-Cola, IBM, and Microsoft have demonstrated great growth over the years, and are the cornerstones of many portfolios. Most investment clubs stick to growth stocks as well.