Before the Doctor
Childhood
Clara Oswald was born on 23 November 1986 in the Lancashire town of Blackpool. She first met the Eleventh Doctor as a young child when she accidentally kicked a football at his head at a park. She loved to attend Sunday school, taught by a "nice lady teacher" in a small church room that smelt of oak polish and had felt-tip colouring on the walls.
As a child, she liked travel books and science kits but did not like hair products. She was taught about Amy Johnson in school, who became her role model throughout her childhood. Clara visited many National Trust houses in her childhood. When she was young, she was once stung by a wasp. As a child, her nan took her to the Blackpool Tower circus.
When Clara was nine years old, her father, Dave, took her on a trip to a tower block near Southport with a restaurant at the top. The restaurant had a solid clear glass floor, but Dave assured her it was "safe as houses". Two lads inside the restaurant started jumping up and down on the glass, shouting they were going to break it in "language Dad later said did not suit young ladies". Since then, Clara was not very keen on heights, or indeed glass floors. At this age, she also stopped believing in Santa Claus, later explaining this was her growing out of fairy tales.
Some time afterwards, Clara met the Eleventh Doctor again, when an earlier version of him was sad about not being able to locate Clara. He did not realise her identity, nor did she know that she herself was the "friend" for whom he was looking. She thought the idea of him finding his friend by destiny was "rubbish". As a child, she claimed she was always losing things: her "best pencil", her school bag, her gran and her "mojo", which she managed to get back. Whenever she would lose something, she'd go to a quiet place, close her eyes, then would find where she'd put it. The Doctor considered that he might follow her advice on this to find his friend, an idea she thought made sense.
Clara's mother, Ellie, told her that she "shouldn't talk to strange men", but she spoke to the Doctor regardless. Her worst fear as a child was getting lost. While on a bank holiday visit to Blackpool beach, her nightmares came true, but her mother eventually found her. Ellie comforted her by saying that she would always find her, wherever she was. She passed her driving test on her first try.
Clara was left devastated on 5 March 2005 when her mother died. Clara's father, Dave Oswald, comforted her at her funeral, and the Doctor watched in silence from a distance.
Clara was among the billions of people across the world who had briefly become a part of the Master Race.
Becoming a Nanny
She wanted to travel after university, but before she left, she spent a week with a family friend in Chiswick, London to nanny for Mr Maitland's children, Artie and Angie Maitland. Mrs Maitland died that week and, as the Doctor later put it, Clara felt duty-bound to look after the children.
Meeting the Doctor
Clara had a poor knowledge of the internet. While attempting to log on to the Wi-Fi in the Maitland home, she used a mnemonic device, "Run you clever boy and remember", to help her recall the Wi-Fi password, rycbar123. She phoned a number for technical support, given to her by a woman in a shop, that reached the Eleventh Doctor in the year 1207. Perplexed, she believed that he was on a helpline, and so she requested that he go to her to help her figure out how to use the Internet.
He attempted to assist her, but Clara clicked on the Wi-Fi connection being used by the Great Intelligence to harvest human minds. A Spoonhead, adopting the guise of a character from Summer Falls, a novel she read, uploaded her to the data cloud. The process was incomplete when the Doctor found her, allowing him to restore her. Clara found that her technical knowledge was greatly enhanced as a result of this.
She used this new skill to hack the Great Intelligence's operatives, choosing "Oswin" as a username. She discovered their location in the Shard, before she was downloaded again by a Spoonhead, this time successfully. The Doctor had the entire cloud downloaded back where possible, restoring Clara once more. He invited her to come with him and she told him to return the next day and ask again.