If you are an individual self-directed trader, expect setbacks and failures, especially in the first two years. Expect that your triumphs may be promptly followed by dramatic failures, that you will make mistakes in areas you thought you had mastered, and that any positive P&L may be quickly erased next week. Furthermore, do not expect that your learning curve will be a straight, upward-sloping line. It is far more common for students of any high-level skill to find that their progress comes in a series of jumps interspersed with long, flat plateaus. It is often difficult to maintain motivation during the flat periods–it can be difficult to keep up very hard work for seemingly no reward.
You will hear various stats suggesting that somewhere around 95 percent of self-directed traders fail. The definition of failure, of course, depends on your definition of success… [which] will probably change as your trading ability matures and your personal financial goals shift, but trading success must be both financial and nonfinancial. Be clear that trading is about making money—whatever other motivations and satisfactions are tied into the process, at the end of the day there must be financial reward and it must be substantial… However, it will be very difficult to succeed if you are not absolutely fascinated by markets and the process of trading. If you don’t love it, you won’t be a very good trader, so there must be motivations for trading that go beyond financial gain.
One last thought on this subject: When we look at people who are very successful in any field, we find a very mixed group. They come from different backgrounds, have very different personalities and attitudes, and reached their success through interesting paths, some of which are far from straight. In most fields, it is impossible to find consistent predictors of success, but people who succeed have one thing in common—they did not quit. This is so simple that it seems trivial, but is the common thread tying all of these people together. As Mark Cuban famously said, “It doesn’t matter how many times you fail. It doesn’t matter how many times you almost get it right. No one is going to know or care about your failures, and neither should you. All you have to do is learn from them and those around you because … all that matters … is that you get it right once. Then everyone can tell you how lucky you are.” Commit to the process. Never give up.
(extracted from pp 383-384 of The Art and Science of Technical Analysis)