Purely from a web/application development standpoint, the answer is a little dependent on what direction(s) you are open to taking in terms of the go-forward vision. Most scenarios (side project, part time passion project or full-time head first deep diving) likely commence with the scoping and planning for the project itself. There are a number of feature and functional details you need to conclude so that you can start understanding how your website fits relative to the marketplace and importantly what sort of resources (time/money/people) you will need to get this off the ground. to that extent, I would start with going through a wireframing exercise which will have you outline the rough blocking and tackling for each of the major application screens (both front end and back end/admin). That, along with an outline of your DB and researching/analyzing whch third party tools you will need in addition to your site (CRM, payment processors, etc etc) should give you a document which you can use to shop around the idea to potential tech partners and even investors. Depending on your goal and the depth of the application, this could be a document anywhere from 30-90+ pages and is a critical first step towards building a successful implementation strategy and product roadmap. I'd be happy to connect and walk you through the scoping/documenting/planning processes further and offer any other insights or help I can from there. Just request a meeting and we can dive further into your upcoming project needs.