First of all, make a list of all the things you want from the new bathroom.
A roomy, well -lit shower, sharp edge appliances, water flowing tubs, nice view, etc.
Don´t forget to consider the reality. Now is the time to identify the practical issues that will set limits on the design. These are the hard realities: budget, building codes, the physical and structural limitations of the space, the feasibility of changing plumbing and wiring, and the amount of work you intend to do yourself.

Do not view these issues as obstacles to creating a wonderful design – view them rather as opportunities for creative problem solving.