What will you need to complete the task ahead?
Hopefully you have collected together quite a bit of research - It certainly be a good idea to begin now to analyse the good bits of what you have found out - Have you access to all the tools and equipment you will need?
From where will you get the materials … How will you shape the materials …
… Are there any processes that will be necessary to use during the making (like tapping threads, CNC milling or brazing for instance) that will require separate planning and preparation? Now might be a good time to make a check-list of all these minor problems and tasks.
Do you need to find out anything - or learn new skills - rapidly!