What should I do to prepare for SPFx web part development?

 Ans:-

Here are some of the things that you can start doing in anticipation of SPFx web parts:

-Move all code to client side JavaScript as much as possible and using JSOM for all SharePoint transactions

-Change all server side code to make CSOM calls instead of in-process SharePoint API

-Start using Typescript wherever possible

-Convert full trust solutions to provider hosted add-ins wherever possible especially as web services which can be called from client side code