For me also, intuition usually surfaces as feeling. Sometimes, as Constance says, it is a lack of feeling, sometimes, it is a knowing. We just "know" what is or what is not. I have learned to listen, to feel, to test and to act carefully. Sometimes I feel I should not be too deliberate, although it is hard to act against a feeling. Anyway, I rely on this wonderful sense more and more and am always grateful when it is very clear.
Someone said to me once--you cannot "know" this thing that I said I knew. However, we know that we can know, as it is God in us who does the knowing!