Never store carpets vertically on one end. The weight of the carpet can crinkle and crease that end, disfiguring it permanently.
Placing heavy furniture on a carpet is a sure-shot way of causing dents. Thankfully, treating the indentation is easy. Start by wetting the area—either let an ice cube melt over the patch, or use a steam iron for the task. Blot the excess water with a clean rag cloth, then run a comb over the area to get the fibres back in shape.