Different degrees of trading skill

1) Level 1: Buy on a whim , sell on a whim
2) Level 2: You realize that maybe there are some patterns. So you buy/sell news or on calls given by 'experts'. At this stage you probably try to focus on accuracy of trades. You obsess with being right.
3) Level 3: You realize market doesn't always go up on good news and down on bad news
You start seeing support/resistance/chart patterns and the 'trend'
4) Level 4: You realize that some stocks even when they break support are strong and others even when they break resistance are weak. You pay attention to not just the short term trend but also the long term trend (long term trend is usually connected to the fundamentals).
5) Level 5: You come up with plans, entry area, stoplosses, targets (fundamental or technical).
6) Level 6: Your understand that just because someone is right more often than wrong doesn't make him richer. You understand the importance of risk management

Expected profit (n trials)= (Avg profit * % profitable - avg loss * % losses )* n
You spend time on testing ideas before you use them. You stop following what everyone else is saying and instead start appreciating the underlying probabilities.
Most people start following a trading system at this point and learn to keep their emotions in check by following what their system says.

7) Level 7: You subonscious is aware of all of the above and trading is instinctive. You feel the good vibes in a stock's chart/fundas/news instead of having to trust someone elses view. You trade your own view consistently and profitably with minimal effort.

Tests on expertise:

http://scientificamerican.com/print_version.cfm?articleID=00010347-101C-14C1-8F9E83414B7F4945
http://www.sciam.com/article.cfm?chanID=sa006&articleID=00010347-101C-14C1-8F9E83414B7F4945&pageNumber=2&catID=2