How to make an effective resume?—It's easy! What it all boils down to is how clean and comprehensive its layout and overall format is written.
One key part of making a great resume is by formatting it to look simple, but substantial. Use professional looking fonts (e.g. Seriff fonts) to give a professional look to your cover letter. Your font size should be between 11-12. And, since most resumes are typically scanned for about 10-30 seconds, make good use of bold and italics to guide your potential employer's eyes to the key parts of the resume. Doing so will make it easier for the reader to absorb the pertinent parts of your cover letter.