I am a biochemist (PhD student) at the Heinrich-Heine-Universität Düsseldorf and started mapping for OSM in March 2008. This was back at a time when the best aerial images we got came from Yahoo and were of mediocre resolution at best. For southern Düsseldorf they even did not reveal anything else than cloud. In those days, I focused mainly on tracing streets and ways in Düsseldorf-Hellerhof and Garath using GPS tracks.
Currently I use publicly available open data provided by various sources (state of NRW, public transport networks e.g. VRR), combined with my own observations. In recent times, I was mainly involved in mapping public transport facilities in Düsseldorf and adding street attributes (e.g. turn lanes).
My current mapping area is Southern Düsseldorf. I used to map mainly Düsseldorf Hellerhof, a suburb in the very South of Düsseldorf, but recently moved to Düsseldorf-Wersten, which shifted my mapping focus a bit. Nevertheless, I keep things up to date in "my old area" as well ;-)
- Garmin Oregon 450