My daughter already knew the alphabet and the sound of each letter at quite an early age, partly through going through letters and sounds with me and my Mum, and partly through watching Sesame Street, which also helped with counting etc, but I didn't make a conscious effort to teach her to read until a couple of terms before she started school. We had always read to her a lot since she was tiny, and we talked constantly. She went to nursery for two afternoons a week for about six months before she started Reception and I was told by the nursery when she started that she was one of the only children who couldn't read, and I think seeing the other children reading made her want to learn even more. She really wanted to be able to read, and had a huge thirst for knowledge We worked through the Ladybird Peter and Jane books at first, and they really suited her. We spent about half an hour each day going through the books together, and she often spent extra time trying to read them on her own. My daughter had various other books with pictures and words which helped to increase her vocabulary, and she was able to sound out unfamiliar words quite well. We are fortunate that we live within a ten minute walk of a lovely museum, which is very child friendly, and my daughter had at least two trips there each week. We live in south London, so also have easy access to lots of other museums, as well as a couple of city farms, and much bigger farms within an hour's drive.
I think I was also aware that when I started school I was able to read fluently, and knew some of my tables, and just assumed that was normal! Once my daughter had started school, I went in to read with the children in her class once or twice a week, and realised that most of the children couldn't read. I remember one little girl in particular who didn't even know any colours, let alone letters or numbers, and she came to school dirty, smelly, and hungry. But she was so desperate to learn, and really thrived at the school. By the time my daughter left at the end of Year 2, the other girl had caught up with most of the others in the class and was doing really well. It wasn't an issue in Reception that my daughter and a couple of the other children were much more advanced in their reading and writing than some of the other children, and they were given differentiated work and more difficult reading books.