Highly liquid stocks or ETFs to reduce transaction costs:
Find good quality, high dividend paying, & optionable stocks.
My method with the latest refinements is -- start off with good value companies (broken stocks not broken companies or business models) and look for a good entry point using the technical analysis. Even then, enter by selling Put options. If I end up buying the stock, sell covered call options in sideways movement or take profit when the uptrend is broken. Leave profits in an index fund or ETF.
Ensure that the stock is showing good price action.