So start here? http://en.wikipedia.org/wiki/Trend_estimation trend estimation is the application of statistical techniques to make and justify statements about trends in the data. Assuming the underlying process is a physical system that is incompletely understood, one may thereby construct a model, independent of anything known about the physics of the process, to explain the behavior of the measurement. In particular, one may wish to know if the measurements exhibit an increasing or decreasing trend, that can be statistically distinguished from random behavior.
Son, the trend you see is not a trend. My son told me he saw a lake on the road ahead of us when we were driving on a hot summer day, I told him: "Son, the lake you see is not a lake."
No, you don't have to identify a trend before you trade it. The idea is to trade and identify simultaneously. If you wait for positive identification, you will get there too late. Many experienced traders trade first and identify after. If you trade size you need to do that. Ron
Bundlemaker posted a video on drawing channels, which can be used to identify trends. You can do a search on ET to locate the video.