Sending large files
I dare say most people have got their own favourite ways of sending big files - photographs, videos etc - but if anyone hasn't and wants one, https://wetransfer.com is brilliant. The publishing trade runs on it and no doubt companies pay for the extra facilities you can get, but I've used it free several times a week over many years for sending book spreads back and forth and it has never, ever let me down. You get an email to let you know when the recipient has downloaded what you've sent. If you've got several files, it's quickest to zip them together (highlight and compress on a Mac, no doubt something similar on a PC) so you can upload them with just one click.
