You have two great pieces of advice alread:
stay alert
also to get to know how your mind works
It is amazing what your mind can do (and do to you). It can flat out mess with you.
It is a bit funny but I often take out a group of high school students, or hike solo. With the group or by my self I have never really done anything stupid, but with my girl friend in the Zion Narrows, I was more at ease and stupidity was soon to follow.