I love technical analysis, and use candlesticks as part of my technical analysis system for trading mutual funds in my 401K. However, I would never use a candlestick chart on its own. I use combination of candlesticks, 2 different EMAs, MACD, bollinger bands, RSI and hand drawn trend lines that I constantly tweak. That's about as much data input as I can handle, but it is possible to graph it all at once and see it at a glance if you have the right trading platform.
My approach is very personal, not very aggressive, and took me years to develop. But it's fairly effective - 90% + of my trades are winners. The big advantage of technical analysis is that it forces you to create repeatable rules around which you base your trading. A lot of the time I have little attention at all on what fund I am trading or why it is doing well in that particular market condition. It's basically irrelevant as the technical system tells when to buy and sell, and stops you trying to second guess whether housing, chemicals, gold or asian tigers are is doing well right now.
If you don't keep to your own rules, you have only yourself to blame. This keeps you from blaming the market, which is completely out of your control.
I explain many of my trades with anotated graphs at http://neurotrade.blogspot.com/
investment-strategies
tag is appropriate. Surely this is trading, rather than investing?