Roll a carpet seam roller back and forth horizontally and vertically over all carpet seams. Seam rollers are relatively inexpensive and available at carpet installation centers.
Adjust the light. Wool carpet seams are less visible when they run parallel to the light. Arrange any standing lamps or track lighting so they shine in the direction of the seam. When guests come over, close any windows that shine across the seams.
Vacuum across and along the seams regularly. The vacuum's suction and brushes fluff up the carpet fibers and help them spread over the seams.
Reroute traffic. High volumes of traffic compress the piles of the carpet and make seams more visible. Rearrange furniture in the room so the majority of traffic doesn't travel over the seams.