People often buy stocks they're comfortable and familiar with, like an old pair of shoes. Usually these are lagging slowpokes rather than leaping leaders. It is really important to look at how your stock is performing in relation to the overall market. Avoid laggard stocks and look for genuine leaders. It takes big demand to move a stock significantly higher in price.
Institutional buyers are the most powerful source.
You don't need a large number of institutional owners, but should have at least a few. No institutional sponsorship in a stock is a bad sign because odds are that many institutional investors looked at the stock and passed it over. Another good thing about some institutional sponsorship is that it provides buying support for the stock. By the time performance is so obvious that almost all institutions own it, it is probably too late. Pay attention to whether the number of institutional owners is increasing or decreasing.