Screenshots of what you're doing.

Thank you Mario. Anyway: I was asked today to make use of some other software and I quickly (4 hours) made the rock model. Tools I used are available for free, all textures are GPL friendly.
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some texturing and final result:

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I have problem with seams. It seams that my model is not textured properly around the edges. Any tips how to deal with it? Why it happens?
I found about MESHLAB for optimazing your models and it makes wonders! I highly recomend it. I was able to go down (town) to less then 10 000 triangles.
I also encourage mappers to use XNORMAL for baking normal maps. All you need to do is to inport there 2 versions of your model (with UVW's): Low poly and High poly. The software will do the rest for ya.
EDIT: I managed to fix the seams and I created small map with floating rocks:
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