feel one's way; tread carefully(You should tread carefully when buying tires because the right choice can affect their performance and how long they last.ART Vancouver)
pussyfoot; dip a toe in the water(Вместо артикля может употребляться соответствующее притяжательное местоимение. VLZ_58); tread softly(There are cost overruns on the two projects that we are building in Denver, so we have to tread softly and learn from mistakes made in the past. ART Vancouver)