The current and most basic definition of consciousness is the state of being awake and aware of one's surroundings. Of course the medical and psychological fields are trying to improve the definition of consciousness and rewrite what it really means, but I think it is best to base this answer of the basic term and definition. With that being said, I do believe humans achieve consciousness on a daily basis.
I think a clear calm view of the world without distractions and issues can push someone to a level of consciousness. It really depends on what your view is on the subject, some may need just little to achieve a lot. If you think consciousness is a level in which float into the sky and become one with the earth, its not. You achieve personal consciousness, through your own goals and means.
Humans do achieve consciousness, even though many humans act based on their unconsciousness that takes place every second, even while I am writing my supporting argument. The only way to achieve this consciousness is to escape every reality and step back from your own self. It is to stop the natural flow and think about every choice and why you are doing what you are doing. One has to be completely be absorbed into their mind to achieve consciousness.
I do not think we ever fully achieve consciousness because of the things in society that grab our attention and bog us down. While it's a myth that we only use 10% of our brains, it is not a myth that we are not living up to our greatest potential.
No, I do not think that humans ever really achieve consciousness, because humans can experience so little. Humans are on the planet for such a brief period of time. They can only see and experience what is in front of them. Without complete information, humans cannot ever truly experience consciousness.