Have A Trading Plan

Whether they use a strictly mechanical trading system or a set of general trading principles, successful traders have concrete trading goals and logical plans (based on market behavior) to reach them. They do not wish or hope for trades to go their way, expect trading to be painless, or look for instant success or overnight millions.
Through careful study of the markets, they develop an idea of what is possible, establish reasonable trading goals, and implement a plan to achieve them.

–from the TRADEHARD.COM Guide to Conquering the Trading Markets (1999, M. Gordon Publishing, Malibu, Calif.).