Hi John, sorry this post failed when I tried several times over the weekend...darn phone!
When I started out in G, I wanted to carve stone in pizza bases like Simon Andrews, so to get an idea of the scale, I printed a sheet of brick and a sheet of stone off and took 'rough' measurements from those to give me an idea of the general size to work with. Pretty theraputic it was too scribing out my little shed
Even want to make another one!
The tiles were watercolour paper cut into strips with 1mm gaps between tiles and about 3mm at the top to layer the other tiles over, the idea is explained in more detail in this excellently useful thread: http://forum.gn15.info/viewtopic.php?t=944
Hanging basket liner has produced some disastrous results for me, but then I could have been doing it wrong, instead I used static grass fibres from a puffer bottle:
All that cost something in the region of £15 to set myself up, and I have enough left over to do an entire 'proper; sized layout...it's worth looking at http://www.internationalmodels.net/
for other scenic bits...just don't get carried away
Animals...Gerry has answered your question really, unless you're a skilled modeller with milliput