Functional resumes are good when you have little to zero work experience (or new grads). This type of resume allows you to showcase skills that fit in with the job requirements. Fair warning: most recruiters and hiring managers dont like this format and feel as though you may be hiding something. If you have a chronological resume you do not want to have one part chronological and one part functional because it will throw off the entire formatting and may confuse the employer about your skill set.
Functional format is best for those who are switching their career or have large employment gaps on their resume. In this format, you dont have to list the joining or resigning dates of the previous employments. Functional format will hide your employment gaps or your job switching.
Make your resume original Make sure your resume stands out from the crowd. Dont be afraid of trying something different or breaking from the mold. Sometimes a little creativity can garner enough attention to get your resume read which can make all the difference. Dont overdo it though. Being wacky or silly may be a part of your personality but usually is not a desirable quality in the work place. Photos are usually a bad idea as well. Be creative but keep it simple to avoid drawing attention away from what is really important.
Avoid being vague If you have references include them. Dont say available upon request. If you have gaps in employment explain them clearly. They will probably come up in the interview anyways. Being prepared in advance by giving complete information in your resume is better than being caught off guard in the interview or worse skipped over all together.
Use proper formatting Make sure to avoid excessive white space and to use the space on the page. Avoid using more than one page if possible definitely no more than two. Highlight key points with bullet lists and make sure your paragraphs are clear and concise. Resumes are not the time to be wordy. Be straight to the point.