Generally when a student is first starting out learning scuba diving, the details can be inundating. They no doubt are energized about learning to dive and are not particularly patient. It is easy to realize their enthusiasm, it is still essential to know the facts and know their origin. The concern over plausible and realistic statistics has been brought to light with the internet for understandable reasons. Sometimes even with the best intentions; people for some reason print deceptive ideas. Be sure of the foundation from which your information comes.
Most experienced divers understand that by controlling how much air they breathe during a dive, they can stay under much longer. Divers that have been doing this for decades understand the benefit of control breathing, which simply means they know how to breathe underwater just like they do when on dry land. Breathing naturally while underwater is not something that novice divers are capable of doing.
One way to contribute to greater efficiency is do more diving! The reason for that is you will be much more relaxed underwater the more you are out there getting more experience. Though this seems very simplistic, it is the best way to improve.
The next thing that you need to consider is developing breath control, something that most beginners do not have. It is, by far, much more difficult than people believe, simply because you are not breathing the same way that you do on an everyday basis. Some novice divers will actually try to hold their breath while underwater, something that they should not do. Not breathing is directly related to how buoyant you are; you must never stop breathing or your buoyancy levels will begin to erode. Another common problem with breathing is to breathe much too rapidly causing you to get too much oxygen which is also problematic. Keep these things in mind as you learn more about buoyancy and breathing in relation to scuba diving.
Be certain to equalize in the beginning of your dive and repeat frequently. Divers with experience advocate going through the equalization steps before you enter the water. This will give your ears the familiarity with what is about to take place. But you absolutely should do this once in the water and keep doing it every couple of feet or so. You can avoid ear problems while descending and obviously this is a good thing. You might discover that one of your ears is not equalizing; when this happens, just turn that ear to the surface.
No matter how good you are diving, never become complacent about your abilities which may lead to a dangerous scenario. You could actually make the mistake of believing that you know everything that you need to regardless of what it is. By becoming lax in your thinking, you actually invite more problems to occur. You can check something a thousand times and it is fine, but the next time you use it could be a failure or significant problem.