Here is my initial concept for the main menu:
To edit the main menu itself you need to get into the code a little bit, but there are loads of useful posts on the lemmasoft forums http://lemmasoft.renai.us/forums/ to help if you're new to this. I'll be using a mix of the official documentation, forums and trial and error. For the art I've used a photograph of a sketch I drew and lots of editing in Photoshop Elements (which is pretty good for a light and cheap version). My current favourite thing to play with in Photoshop is layer styles, especially Hue! It really helps getting a saturated day glow look which I'll definitely be utilising a lot.
To keep on track with this project I've added in timeslots on Google Calendar with little notes like:
Install RenPy and create project (yesterday)
Quick menu screen mock up (today)
By breaking the project up into these tiny tasks I hope that I will stay on track and not get daunted by the scale of all the asset creation, development and testing!