First and foremost, adequate training prior to scuba diving is THE MOST IMPORTANT TIP; scuba diving is a sport that demands your undivided attention, a keen mind, and confidence with your own scuba skills. It's indeed necessary to have proper training since you can save your own life if you know exactly what to do in an emergency. Proper training will help you feel much more comfortable underwater, which is essential for a safe dive. Choose dives that are appropriate for your level of training, experience, and confidence. This is the only scenario in life where you stay  in your comfort zone! Listen to your inner voice.