Keeping the bacon very cold makes it much easier to cut.
Preheat oven to 250°.
Arrange crackers on a work surface. Cut bacon lengthwise into thirds and then crosswise into thirds. Wrap each cracker with 1 or 2 pieces of bacon to resemble ribbon on a package. Arrange in a single layer on two parchment-lined baking sheets. Bake at 250° for 1 hour or until bacon is crisp. Tuck 1 rosemary tip under bacon on each cracker. Cool on a wire rack. Serve warm or at room temperature.