1. You're going to see people advising you to use a pen instead of a pencil.
The theory that you should use pens rather than pencils to avoid your vote being erased dates back to pro-independence voters in the 2014 Scottish independence referendum, and was adopted by Leave voters in the 2016 European referendum.
You can use a pen if you like. But there is no evidence to suggest it will protect you from fraud. Last year Jordan Lawrence from the Electoral Commission told the Daily Mirror: "The use of pencils does not in itself increase the likelihood of electoral fraud: while pencil marks can be rubbed out, similarly, pen marks can be crossed out."