I have been using eCog for quite a number of years now. If you are a traditional imager processor, forget just about everything you know. This software takes a very different approach to processing imagery. On thing I found very help full were the tutorials in the back of the manual. I was able to find an example very close (same imagery type) to my own work. I stepped though that with my own imagery. This gave me a good feel on how I might approach my own project. I have just started a new project and have spent a lot of time just on segmenting. In my case I wanted to break out the water area from everything else. It is much easier to work in steps - I start with the largest items, classify those then start working on other items at diferent (smaller scale) sizes. It often takes a while to get the scale, color, shape parameters correct to be able to get the majority, in this case, the stream channels. There are also settling ponds in my image and I have been fairly successful in separating the ponds from the streams which surprised me. It's all in playing with the different segmentation parameters.
I did a presentation for beginners at the eCog user meeting in Philadelphia a couple of years ago. I don't know if it is on the Definiens website but I can send it to you if you would like.