You're not meant to be aware of "everything". You just have to try push the limits of your awareness, what you are trying to achieve is becoming a natural at being slightly more aware in general. Being able to easily notice subtle differences in temperature or smell, and noticing things that are out of place etc. It's impossible for any human to focus on all there senses at once.
It's similar to getting in the right hunting mindset, you need to constantly keep an eye out for changes or little signs, not everything, just what will lead you to your goal.

I would say it's better to be marginally more aware for most of the day than largely aware for only 10 minutes.