The tutorial that taught me how to model organic things was the "Modeling a low poly character" at
http://www.montagestudio.org , it's an excellent tutorial though it expects you to have some idea on how to actually model.
Organic modeling was something I used to find impossible a year and a half back, now I don't find it as impossible and tend to focus on it, making a finished completely textured character and seeing how your work has paid off is an enormous rush I'll tell you that.
As for tips, for learning try every single different method for modeling and just look at what style you prefer most, personally I do a mixture between poly-per-poly modeling and cylindrical modeling, but I suggest trying box modeling as well as it's one of the more commonly used ways.
Also always use reference, this I have some issues with at times because there aren't a lot of good free human reference shots out there, but I'd suggest going and purchasing an account at
http://www.3d.sk , they have a giant reference library and you'll probably find absolutely anything in there.
On useful thing is to study anatomy a bit as well, as your model needs to flow through anatomically to work, obviously I'm not saying that you should go and learn every single muscle's name (Though that would be rather cool hah) just generally how the muscles are placed through out the body. And remember to constantly think about the edge loops, because those are what's going to control the flow of your model which is mind-bendingly important on characters.
These are obviously just tips, I don't know a lot of what I just told you but I'm trying, modeling characters is such a joy.
Alucard94, the member of the future of the past.
