There are so many ways of designing and developing of electronic devices, that it is hard to think which would fit your needs and desires. But there are common steps that probably fit in most cases that allow to implement the electronic system from top to bottom:
1) Defining the requirements of electronic system;
2) Collecting information on components to be used;
3) Evaluate the components with respect to the requirements;
4) Block diagram of preliminary design;
5) Do a preliminary timing and load analysis;
6) Define functionality logic;
7) Draw schematic using CAD software;
Do device design and simulation;
9) Perform detailed timing analysis and simulation and adjusting the design;
10) Double-check signal loadings, buffering as needed;
11) Document the design and generate a net list and bill of materials;
12) Generate layout of a printed circuit board;
13) Prototype design;
14) Program the memories and programmable logic for testing.
15) Debug and verify operations using oscilloscope/logic analyser or other debugging tools;
16) Update and complete documentation as the design changes.
Those are general steps and the order may vary or even several tasks may be performed in parallel. Usually software is written in parallel with hardware design prototyping. Usually software development takes much more time than hardware development, so software development may be ahead the hardware development process.
