Because this topic was originally about my OC, Garnet, I think that this might be a perfect place to start revealing the missing parts of Garnet's backstory. Attached is Garnet as a Newborn Foal, Young Colt, and Teenager.
FULL BACKSTORY:
Garnet was born in Fillydelphia as the only son of the unicorn Topaz and the (then well known) earth pony Artistic Vision. Unfortunately, Artistic Vision was called away to the Griffin Empire on a business trip shortly after Garnet's birth, leaving Topaz to care for him by herself. Garnet was raised well, and was taught basic magic from a young age. Eventually, he became so widely talked about in his hometown, that he was accepted into Princess Celestia's School for Gifted Unicorns. Knowing that he'd leave his friends and town behind, Garnet was initially hesitant to leave for Canterlot. Fillydelphia's residents eventually convinced him to leave with the incentive of becoming wider known across all of Equestria.
During his time in the academy, Garnet found himself under intense pressure and often struggled with his coursework, but pulled through by several means of hard studying. At the urging of his mother, Garnet participated in numerous art-based contests, including Poetry, Slam Poetry, and Marching Band, and although he was nearly flawless in all of them, he still hadn't obtained a Cutie Mark.
He eventually found Solace, however, when at the approximate age of 10.57, he was called to the front of the class to work out a problem on the board. Because he was drawing during the initial lesson, he had no idea how to answer it. As he was drawing blanks and cranking his mind to the max, one of the students pointed out something that appeared on his flank: an image of a scroll underneath a garnet gem. The teacher was first to congratulate him on his Cutie Mark, but not without giving him detention for drawing in class.
Near the end of one summer, when Garnet was about 16, Topaz finally told him the truth about his childhood. Artistic Vision wasn't really away in the Griffin Empire, he was killed by a runaway Carriage almost immediately after leaving the Hospital. Now believing most of his life to be a lie and harboring resentment towards his mother, Garnet locked himself in his room, missing days of school on end and becoming malnourished. After a quick tongue-lashing by Princess Celestia herself, Garnet finally agreed to resume his life and make up his studies.
Fresh out of the academy, Garnet worked for a small but profitable company, eventually earning enough to buy a house in Canterlot. For awhile, nothing happened, and Garnet grew bored, eventually giving up any hope that his life was going to take a turn for the better, he was told that there were a few aspiring artists in the nearby town of Ponyville. Packing his things, selling his house, and bidding farewell to his Canterlot friends, Garnet excitingly prepared for his new life in the small, quiet town.
Well, waddaya think?