We highly recommend watching some videos on YouTube, in particular a YouTuber called Thomas Nagy.
There are countless videos that are informative and fun covering all aspects of the industry and will give you a good understanding of what the day to day life of an electrician is like:
Accuracy is key within the industry; for that reason, researching measuring techniques and conversions from meters to millimetres would be a beneficial to you as well as transposition of formula. You will be required to wear safety boots in the practical workshop so start thinking about getting a pair. I would recommend Screwfix.
The electrical team highly recommend purchasing the course textbook to aid your studies (pictured below):
The City & Guilds Textbook: Book 1 Electrical Installations (ISBN: 978 1 5104 3224 6)