It i time to start now! First, you need to choose the right paper. Make sure it is thick, so it will stand still. Draw a cactus, and you can add lines too if you want. See the example below. Despite the cactus form, draw a copy of the body of the cactus too.It will give the 3D look to your cacti.
Carefully cut a straight vertical line, that is long about 3/4 of the cactus. Insert the second part in it. Now you have a 3D cactus that looks awesome! You can put it in a decorative pot, as a regular one. For additional decor, you can add flowers too!