Okay, so I’m a beginner at mnemotehnics and memory in total. That is also true for remembering numbers and their recall.
I’m still learning the 0-99 number list(am using the Dominic system), and have come as far as to the 50th number.
The question is: how do you practice the number recall? How did you start doing it?
For training, you can print out some sheets of random numbers.
Memorize them.
Recall them on a blank sheet of paper and then compare your written numbers with the originals.
If you just want to practice converting the numbers into images, print out a few sheets of the random digits and carry them around in your pocket. You can practice converting them into images during the day. This script was designed for that purpose:
Each 2-digit number is listed once, you can get equal practice converting each number into an image. 
Thanks man 