Germany has a shortage on skilled and academic workers. Persons lacking any kind of training will not have a chance to obtain a residence permit in Germany. The individual articles will describe you what you need to know for a certain residence permit around employment in Germany.

Blue Card EU for Highly Skilled Persons to Work in Germany
D-Visa: Working Holiday Visa for Germany
German Employment Visa Requirements
Getting a German Work Permit
High Professionals in Germany - Residents Permit Full Legal Assistance
Intracompany Transfer Permit for Germany
Migrating inside Europe