As a university professor I see students admiring the work of professional artists and learning as much as they can about 3D to get where their heroes are. Part of their awe focuses on the amazing skill needed to create something at a high level and the rest of their focus is on the creative idea. They dream about the epic project that they themselves will create as soon as their skills are strong enough. It is always enjoyable to teach students who dream; everything is exciting to them.
When the time finally comes to create anything they want, no restrictions or limitations, many students freeze. They sketch out idea after idea but they become indecisive and claim every idea is not good enough. There can be a lot of pressure behind creating your own project, especially when you have the skills to achieve anything you want. So what do you do?
Just One of Many
Pressure and indecision can sometimes stem from thinking that this project is the one project that will rule them all. When in reality this is just one of many and it is likely that your future projects will be more refined and more creative than whatever you are currently planning. The more you create the more you grow as an artist.
Creative freedom can be terrifying and easily turns your list of ideas into a list of none. There are many ways to introduce boundaries into a project and what this does is transform creative decisions into problem solving. Instead of spinning in circles and spending hours running through all the possible options, write yourself a project outline that describes the requirements.
Don't Edit Yourself
My favorite solution is to simply resist the urge to edit your idea. Don't worry about whether or not it is a good idea, instead follow your instincts and create something; it doesn't have to make sense.
Whatever it is you choose to create, be sure it is something you are excited about and invested in. 3D takes a long time and you need to be dedicated. It is completely normal to keep multiple projects going at the same time and bounce between them.
When you truly can create anything, why not make it all?