According to Osho, you don’t “do” openness; you allow it. The mind has two unconnected halves: the doer (effort) and the non-doer (effortless). Your question comes from the doer, which cannot understand letting go. Become available by relaxing into the non-doing side—Taoist/Zen receptivity—without striving or analysis. Transcend both compulsive effort and mere thinking; simply rest, and openness is already there.
Stop trying to make openness happen; relax and let your naturally open side show itself.