backup is my data and then take an image of your current installation.
What may happen on the 29th and following is a flood of concise and exhaustive official 'HowTo' guides for Windows 10 from MS themselves and, we beta testers, who have been bustin our buns for the last six months helping MS get this 'show on the road', with virtually no help from them I might add, are gonna look like a bunch of 'you know whats' because we may have gotten one or two details incorrect!
I wouldn't put myself down. There is probably more real experience here than in dozens of technical support centers that will be dealing with Windows 10 in a few days time. They are going to be having the roughest time - for us no pressure.
I don't have problem with that but don't want to wake one day up, boot to 8.1 and end up with 10 instead and my insider account turned off. Turned net inside out and upside down but question if I will loose insider rating when I upgrade 8.1 to 10.