Put everything in its place
When you cook, particularly if you cook often, you likely don't get out one ingredient and put it in the pan, then get out another ingredient, use part of it and put the rest away, and then get out another ingredient to add to the pan. You probably get out everything you need, and then commence. (It's called "mise en place," a French phrase that roughly translates to “everything in its place.”) Cooking is easier if you have everything in its place before you begin.
Lots of other tasks are easier when you practice mise en place - doing your taxes, wrapping a gift, changing the oil, making a craft, paying your bills, studying for a test....
Why is this so much better?
It allows you to then fully concentrate on the task instead of consistently stepping away from it to get something else. This also minimizes the risk of error.
Not having to step away from the task also minimizes distractions. (Which reminds me, when you are putting everything in its place, make sure you don't have items you don't need, such as your phone or other distractions.)
You'll feel a sense of accomplishment that you've been able to start and finish a task in a relatively short time.
When you start thinking about mise en place, you may find you need to change where you store some items. If you are walking from one end to the kitchen to the other to get items you often use together when you bake, can you move one item so it's closer to the others? Would it be helpful to buy an extra roll of tape and a pair of scissors to keep with your wrapping paper? Do you have a folder with all your tax paperwork?
If it's impractical to store items in the same place, consider a small checklist so you can be sure to get everything before you begin. This is why recipes are helpful - they list all the ingredients before they list the steps. I've done this with my taxes, listing W-2s, business receipts, mortgage paperwork, bank statements, charitable giving records, and so on.
About to begin? Put everything in its place first.