Before you start writing your skills section, carefully review the job description and identify the key skills required for the role. Principal software engineer positions typically require expertise in:

• Programming languages: Java, Python, C++, etc.
• Web technologies: HTML, CSS, JavaScript, etc.
• Frameworks: Spring, Angular, React, etc.
• Databases: SQL, MongoDB, etc.
• Cloud platforms: AWS, Azure, Google Cloud, etc.

Make sure to include these skills on your resume, especially if they are listed as requirements in the job description. This will help you pass the ATS filters and catch the attention of the hiring manager.

Grouping your skills into categories makes it easier for hiring managers to quickly scan and understand your expertise. You can categorize your skills as follows:

• Programming Languages: Java (Expert), Python (Advanced), C++ (Intermediate)
• Web Technologies: JavaScript (Expert), HTML5 (Advanced), CSS3 (Advanced)
• Frameworks: Spring (Expert), Angular (Advanced), React (Intermediate)
• Databases: MySQL (Expert), MongoDB (Advanced), PostgreSQL (Intermediate)

Including proficiency levels gives the hiring manager a clear idea of your level of expertise in each skill. However, make sure your proficiency levels are honest and accurate.

Skills: Programming, Databases, Web Development, Software Engineering, Agile Methodologies, Problem Solving, Team Leadership

Avoid vague or overly broad skill categories, and do not include soft skills like "Problem Solving" or "Team Leadership" in this section. Instead, focus on specific technical skills:

Skills:
Programming Languages: Java (Expert), Python (Advanced), C++ (Intermediate)
Web Technologies: JavaScript (Expert), HTML5 (Advanced), CSS3 (Advanced)
Frameworks: Spring (Expert), Angular (Advanced), React (Intermediate)
Databases: MySQL (Expert), MongoDB (Advanced), PostgreSQL (Intermediate)

As a principal software engineer, you likely have a wide range of skills and experience. However, it's important to focus on the skills that are most relevant to the job you are applying for.

For example, if you are applying for a position that primarily uses Java and Spring, focus on those skills and technologies in your skills section. Don't waste valuable space on your resume listing outdated or irrelevant skills.

Skills: Java, Spring, COBOL, Assembly, Fortran, MS Office, Windows 95

In the example above, outdated technologies like COBOL, Assembly, and Fortran are unlikely to be relevant for a modern principal software engineer position. Including them on your resume may even make you seem out of touch.

Skills:
Programming Languages: Java (Expert), Python (Advanced)
Frameworks: Spring (Expert), Hibernate (Advanced), JUnit (Advanced)
Web Technologies: JavaScript (Expert), React (Advanced), HTML5 (Advanced), CSS3 (Intermediate)
Databases: MySQL (Expert), MongoDB (Advanced), Oracle (Intermediate)
Tools: Git (Expert), Jenkins (Advanced), Docker (Intermediate)

Many companies use Applicant Tracking Systems (ATS) to automatically screen resumes and filter out candidates who don't meet certain criteria. To pass the ATS and get your resume in front of a human hiring manager, it's important to optimize your skills section.

One way to do this is to use the exact keywords and phrases from the job description in your skills section, where applicable. For example, if the job description lists "Experience with Java and Spring Framework" as a requirement, make sure to include "Java" and "Spring Framework" in your skills section.

However, don't simply stuff your resume with keywords. The ATS may be sophisticated enough to recognize keyword stuffing, and it will be obvious to the hiring manager when they review your resume. Instead, focus on including relevant skills that genuinely reflect your expertise.