I also think that it's better to have some idea of the details of my world before I start writing, just because the story can be a lot more naturally shaped and influenced by the culture, rather than the culture fitting to the story. I feel like it'll be a lot more natural, readable and realistic (in terms of how natural the society seems, rather than how realistic it's going to be. I have a feeling a fantasy book probably won't be TOO realistic...).
So, for example, I've decided on two forms of transport in Aenoria, both animal based. One is a bear-type creature that can be ridden in two different ways (with a rather ingenious saddle idea that I'm hoping to upload some kind of diagram of soon... all depending on my artistic skills of course, so that could take a while...) and one is a wildcat creature similar to a Cheetah, but with an extra pair of legs.
I'm also aware that I want to pay homage to some of the fantasy genre stalwarts. I feel like a fantasy book without some mention of Dragons would be a bit of a crime, but I'm also aware that a lot of fantasy books rely quite heavily on Dragons (the Inheritance Trilogy, for example) and I don't want mine to be like that. I'm going to have them ingrained in culture somehow.
I think it would be interesting to have dragons occupy a similar mythological role to that which they occupy in real life. So to have them mentioned in art and literature, but not actually existent as beings in the world.
I'm going to think about this more over the next few weeks, and start to consider things like the religion and political structure of Aenoria, as well as what it would be like to live in Aenoria as a normal person. What would the recreational activities be? How would people interact? Is there to be a class system?
I know there's a lot of big questions that relate to society and culture, and so I'm not expecting to have a fully shaped society after just a few weeks, but I know that starting to consider it can only help me in my writing.
P.s. if anyone is interested, undergarments were worn because any contact between outer layers of clothing and the skin (which was understood to expel unwanted, and often unpleasant, things from the body, such as sweat) was not socially acceptable. This links to the idea that outward appearance was very important, and cleanliness and appearance were expected to reflect your position in society. So if a member of the upper classes had any evidence of secretion, sweat, dirt etc. from the skin on his outgarments, then it was seen as very shameful.