Before guides are wrapped in place, the guide feet or foot must be filed or ground to a tapered end. As manufactured, most guides do not end in a smooth tapered edge, but rather in a blunt end.
Without preparing the foot, thread will not smoothly cover the end of the foot and will result in a gap as the thread jumps from the smooth rod blank to the guide foot.
File or grind the foot at an angle until it has a tapered edge. After preparing the top side, check the bottoms for burrs or imperfections that might damage the rod, and use a file to remove and smooth any such spurs.
After preparing the guide feet, make sure you haven't bent them up or down. If so, place the guide on the blank and check to see if the guide foot is straight edged with the rod blank. If it is not, remove the guide from the blank and gently bend the foot into a straight edge. Secure the guide in place, and wrap.