Multi-Tasking should really be called doing many thing poorly. The human brain just isn't wired for it. I'll try to prove it to you with an example.
Take a piece of paper and do this.... writing M, then 1... U, then 2... all the way through the word multi-tasking and the numbers 1 through 13 (including the hyphen). Time how long it takes you to do it.
Now try this... simply write the word multi-tasking first and then the numbers 1, 2, 3... all the way to 13. time that.
This is a simple example, and sooner or later, if you practiced it enough, you could get the hang of it. But, the bottom line is we are not made to do this, so why bother. Let's commit to doing things well the first time.
My grandmother used to say;
"Once a job has first begun, never stop until it's done. Though the job be great or small, do it right or not at all."
I don't think she struggled with multi-tasking, but her words were prophetic.
If you don't believe, ask Google.