Hi Bitbyter, Pasis's tutorial is a gem, isn't it?
If you want to get rid of obvious edges on tiles, you need a seamless tile. Even with seamless tiles edges can be apparent, so it is often a good idea to overlay another texture or two on top to hide the seams.
As for the mountains, I'm not sure if I can help here, perhaps because I don't really understand the question. Are you looking for a mountain style which is more isometric (mountains seen from an angle?) RobA did a tutorial on forcing perspectives with mountains (you'll have to do a site search) which may be what you're looking for.