You can read everything here (in german), pages 7-15:
https://www.dosb.de/fileadmin/Bilder_allgemein/Veranstaltungen/Rio_2016/Sportartspezifische_Nominierungskriterien_Rio_2016_DSueB_Aktualisierung_20160126.pdf
To sum it up:
Mens/womens air rifle:
There was a competition in Dortmund from March 12th to March 13th for all the athletes who are part of the german "top team Rio" and only top 3 from there are able to qualify for Rio. The second part of the qualification consists of the world cups in Rio and Munich (May 19th to May 26th), so we will know the qualified athletes after the world cup in Munich. The results from those 3 competitions (Dortmund, Munich and Rio) will be "added" to determine the qualified athletes.
Current standings:
Men: Justus is clearly in the lead, he finished 4th in Rio. Janker was 44th and Schallenberger was 72th.
Women: Gschwandtner was 3rd, Kreutzer was 8th and Engleder was 10th, still very open.
Mens 50 m rifle prone:
Brodmeier and Junghänel are basically qualified (they are the only 2 members of the "top team Rio" in this discipline). DSB (german shooting federation) cant nominate athletes, they are only allowed to "propose" athletes to DOSB ("german olympic committee") and then DOSB has to nominate those athletes, but they basically always nominate those athletes.
Mens/womens 50 m rifle 3 positions:
In this event the national "selection" didnt take place in Dortmund, it will consist of 2 competitions in Plzen (May 4th to May 8th) and Hanover (May 12th to May 15th). The top 3 from those competitions (results will be added) will be allowed to compete in Munich (May 19th to May 26th), the final part of the qualification, all results will be added.
Mens rapid fire pistol:
Results from the two world cups in Rio and Munich will be added and top 2 will qualify. At the moment everything is still open. In Rio Reitz finished 6th, Geis finished 4th and Sauter finished 7th (missing the final only by countback). At the moment its not unlikely that Reitz or Geis will miss Rio ...
Mens/womens 10 m air pistol, mens trap, womens 25 m pistol and mens 50 m pistol:
No quota place, so no qualification needed.
Assuming that we get a spot in womens 10 m air pistol or womens 25 m pistol (I dont think that we will try to get a spot in mens trap, mens 50 m pistol or mens 10 m air pistol):
Qualification consists of the World Cup in Munich, one competition in Hanover (May 9th to May 12th) and another competition in Munich (May 26th to May 27th).
Scores will be added to determine the qualified athlete.
Womens trap:
Top 3 from the Grand Prix in Nicosia (March 9th to March 14th) and the World Cup in Nicosia (March 17th to March 25th) (results will be added) will be allowed to enter the second part of the qualification that consists of the World Cups in Nicosia (June 1st to June 4th) and Baku (June 20th to June 28th). In the end the athlete with the biggest number of top 6 finishes (reached finals) will qualify.
Scheibl won silver at the world cup in Nicosia, so she should be clearly in the lead right now.
Mens double trap:
Qualification consists of the the world cup in Rio and the "Green Cup" in Todi (May 26th to May 29th), the number of finals will decide. (Same number of finals -> Better placement in the final will decide, the same is true for womens trap).
Löw finished 5th in Rio, so he is clearly in the lead right now, Goldbrunner finished 12th.
Mens skeet:
Buchheim is basically qualified (same as in mens 50 rifle prone), because he is the only member of the "top team Rio" in this discipline
Womens skeet:
Same as in mens double trap. Wenzel was the only german athlete who reached the final in Rio, so she is clearly in the lead right now.
In my opinion Brodmeier, Junghänel and Buchheim are basically safe for Rio. Justus, Scheibl, Löw and Wenzel are clearly in the lead and almost safe for Rio.