It all really depends. Is the project for controlling a space shuttle with 200+ people working on it, or is it a hobby project with 1 person.
I'm guessing this is a small project. In that case, do whatever works for you. Write a list of things you think are required. If there are parts you know you need to learn more about or research, get reading the web, try some stuff out with prototype code to see whether it works or not. Don't turn prototype code into real code though, start again with production code and make sure you get all the appropriate error handling etc in.
When you think you've got a good feel for what's needed, get coding. If you hit a point where you think it's not working, go back to the design and rethink it and sketch some more diagrams, and then go back to the code again.
It is extremely doubtful that you can work everything out in your plan and that's how things will actually work out. So, there's little point in trying to plan too far ahead because you'll be wasting time. Just plan out far enough ahead to keep yourself focused on working on the right things and so that you've given yourself a reasonable chance that the code you're working on will fit the big picture and solve the problem you're trying to solve.