The most important steps in designing are first making sure that the logical flow for the user are correct. Most of us start with paper or white boards and begin to develop a user flow with the necessary inputs for each screen so that when we go from the drawings to the wireframe layouts there is not a lot of change involved.
When the user flow from the wireframes is confirmed logically then we can go to the design.
The design relies on the logic and overall goal of the app. This involves finalizing fonts, colors, icons, layouts etc.. The more experienced the designer is, the faster these stages can be completed.
It is common for designers to use standard chart design elements mostly because they are all ready familiar with most users. I always thought that each project and use cases demand there own considerations. Innovations only come when we are willing to ask questions like, what is this the best way to present this data; could it be done better.
Once the elements are designed I do some sample screens to check how everything will look in real world apps .