Proceed cautiously (5,4,4)
I believe the answer is:
watch ones step
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">proceed cautiously</span>' is the definition.<br/ ><span class="explanation-format__explanation">(I've seen this before)</span><br/ ><br/ >This is all the clue.<br/ ></span>
(Other definitions for watch ones step that I've seen before include "proceed cautiously" , "Be careful" .)