Chronological format is most commonly used. It is best format for recent graduates and fresher applicants. The details in such CV are presented in the bullet-ed points and are categorized into different sections. The skills are generally listed after the career objective and before professional experience details as fresher applicant will not have any eye catching experience details to grab the attention of the employer.
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.
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.