The DVD for Prince of Egypt has a making-of track, which for one reason or another I ended up watching some years ago. And in there, one of the talking heads described that one of the first things they produced for the movie--even before any substantial animation was done--was the title track's music. (Remember that theme, the one that plays while we're watching the slaves being beaten?) The talking head said that having that song supplied a tone for the whole rest of the work.
For me, I've found that I can establish the tone of a work best by throwing together screen mockups in Paint Shop Pro. In the early days of a project I'll spend more time in PSP than I will writing code, as I try to get the look of the game right. Mechanically screen mockups are also useful--for example, to ensure that my hexagonal tiles will actually tile together properly to form a solid board with no gaps, or that my cloud layer isn't so thick that it obscures the game, and so on.
I was going to start Praetor by jumping right into the thick of the battle and putting that engine together, but every time I started down that track I found there were too many parts that had to be done first. So I backed up and started with--of course--the main menu.
The left-hand screenshot is the PSP mockup I put together, and the right-hand shot is live from the emulator. I've darkened the background a bit from the mockup to help the buttons stand out, but when I see how the game looks on the actual hardware I'll have to retune it.
If all goes well you'll be able to play Praetor three ways: playing the campaign (which consists of roughly 100 battles against the computer, with some RPG elements thrown in), playing an isolated battle against a local computer or networked human, and playing an isolated battle as a correspondence game over the net. It's that last aspect that led to the main menu design: in theory you could have a dozen games going, each with a shot clock measured in hours or days. So the main menu evolved into just a list of games that you're playing, and it will show the status of each game (it's my turn, or it's not, or my opponent resigned, or I'm still looking for an opponent, or whatever).