The path of attaining to Rudolf Steiner's objective of Pure Thinking, or alert and aware clairvoyance (what Barfield terms Final Participation and I have dubbed Primary Thinking) is something I have often seen described as a practice of 'strengthening' our thinking.
This is usually approached by a series of exercises devised and prescribed by Steiner - which amount to exercises aimed at single-mindedness, concentration and broadening of subject matter.
But, the history of Anthroposophy indicates that these exercises are a failure. At the very least; the results are slow and modest - and they seem not to lead to a transformation of thinking.
I would advocate discarding the language of strengthening, and indeed any 'effortful' attempts at deepening thinking; because the effort is almost-inevitably coming-from and directed-at the wrong thing/s.
There is no need for strength, there is no need for concentration; Primary Thinking is quite natural, it is always going-on - we 'merely' need to attend to it... That 'merely' is in fact usually very difficult to do, but this is not the kind of difficulty that can be overcome by conscious-striving; more by 'allowing'...
Allowing the Real Self's thinking to come to awareness and deciding that its natural and spontaneous thinking is valid. Is - indeed - direct knowledge of reality.
Read the whole thing at the Owen Barfield Blog