Good advice, obviously, but there are different types of practice. I was always grateful that, amongst other things, my (wider) research group had weekly meetings with talks, mostly from students who were all expected to do it to get practice and friendly feedback. The next level up was a national conference, where you got the chance to do a short talk in a sympathetic atmosphere, where it was frowned on to be hard on students. It was common to rehearse talks for major meetings in front of the group too for comments.
I've been horrified on occasion subsequently to see students thrown in completely cold to give important talks, including at major international meetings.
I've been horrified on occasion subsequently to see students thrown in completely cold to give important talks, including at major international meetings.