2) make sure you have the API in mind

3) choose a problem

4) take a pen

5) take sheet of paper

6) solve the probem

7) ???

8) profit!

There is most of the time (to not say always) several solution to solve a problem, but only one particular solution will be the best...

The thing is there is still no FOSS projects in the wild using graphdbs from which you can copy the designs, but is it really what you want?