Here are the most important subjects for software engineering, with brief explanations:
1.Object oriented analysis & design: For better maintainability, reusability and faster development, the most well accepted approach, shortly OOAD and its SOLID principals are very important for software engineering.
2.Software quality factors: Software engineering depends on some very important quality factors. Understanding and applying them is crucial.
3.Data structures & algorithms: Basic data structures like array, list, stack, tree, map, set etc. and useful algorithms are vital for software development. Their logical structure should be known.
4. Big-O notation: Big-O notation indicates the performance of an algorithm/code section. Understanding it is very important for comparing performances.
5.UML notation: UML is the universal and complete language for software design & analysis. If there is lack of UML in a development process, it feels there is no engineering.
7.Design patterns: Design patterns are standard and most effective solutions for specific problems. If you don't want to reinvent the wheel, you should learn them.
8.Operating systems basics: Learning OS basics is very important because all applications runs on it. By learning it, we can have better vision, viewpoints and performance for our applications.
9.Computer organization basics: All applications including OS requires a hardware for physical interaction. So, learning computer organization basics is vital again for better vision, viewpoints and performance.
10.Network basics: Network is related with computer organization, OS and the whole information transfer process. In any case we will face it while software development. So, it is important to learn network basics.
11.Requirement analysis: Requirement analysis is the starting point and one of the most important parts of software engineering. Performing it correctly and practically needs experience but it is very essential.
13.Dependency management: Library (JAR, DLL etc.) management, and widely known tools (Maven, Ant, Ivy etc.) are essential for large projects. Otherwise, antipatterns like Jar Hell are inevitable.
15.ORM (Object relational mapping): ORM and its widely known implementation Hibernate framework is an important technique for mapping objects into database tables. It reduces code length and maintenance time.
16.DI (Dependency Injection): DI or IoC (Inversion of Control) and its widely known implementation Spring framework makes life easy for object creation and lifetime management on big enterprise applications.
17.Version controlling systems: VCS tools (SVN, TFS, CVS etc.) are very important by saving so much time for collaborative works and versioning. Their logical viewpoint and standard cammands should be known.
18.Internationalization (i18n): i18n by extracting strings into external files is the best way of supporting multiple languages in our applications. Its practices on different IDEs and technologies must be known.
19.Architectural patterns: Understanding architectural design patterns (like MVC, MVP, MVVM etc.) is essential for producing a maintainable, clean, extendable and testable source code.