First and foremost, look out for the Halal Certification Mark on food packaging or signage of halal eateries. This mark is an official proof that certifies their food meets the Islamic requirements of being 'halal'.  Also keep an eye out for eateries that have 'Halal' listed prominently among their other labels such as Vegetarian or Organic. Furthermore, enquire with staff if unsure about whether they serve only halal products – most restaurants should readily provide this information to customers upon request. Besides these physical clues, you could also check online sources for advice from fellow diners who have visited those establishments before.