What is the smartest, easiest, and best way to back up information on my computer?

I’m one of those people where my LIFE is on the computer, as in, if I were to lose the information I have saved on this computer,(documents, videos, pictures, etc.) then I really, honestly do not know what I would do.

I have a MacBook Pro Lap Top (Macintosh). I need something that will have my information backed up on something separate incase my lap top were to be stolen. What I do at the moment is send all the important information I have worked on to my email, I do this once a day at the end of the day, that way if my laptop breaks or something, I’ll at least have it on my emial, but still that’s not safe enough for me. Because email websites crash sometimes!

So please I’m looking for the easiest, smartest, and cheapest way to do this. All inputs greatly apprecited! thank you.