How To Write A Letter Asking For Salary Increment . Research the job groups and salaries of employees at your level. The date on which the letter is written. 50 Best Salary Increase Letters (How To Ask For A Raise?) ᐅ TemplateLab from templatelab.com Note that you should send this letter after asking for a raise from your manager.so, this email acts as a follow up to your previous communications. There’s an increase in the cost of living in your job’s location. You have taken on new responsibilities.