An overview of the job opportunities for physicists can be found at Welt der Physik
Support for your career start is offered by the Career Center of RWTH.
The Studentinitiative Bonding organizes fares with companies and allows the contact with potential employers.
The Webportal pro-physik.de offers an online job market especially for physicists.
For example the Job Shadowing is a very interesting opportunity.
An opportunity to get contact to comapanies in the region of Aachen is the Job-Caching.
On the pages of the Career Center you can also find tips for your applications.
Other intomations about the start into the job you can find on the web page Berufsstart.