Use a spoon to guide your eyeliner placement
There are a ton of eyeliner hacks floating around the internet, but most involve spending money on useless stickers that will make the ink run and will rip off everything you have underneath. Of course, you can use a piece of thick paper or cardboard as a stencil, but why not try using something reusable instead?
A spoon will work wonders, and the best part is that you can wash it and use it as many times as you want. The handle will help with the lower lines, and the curved part will serve to get a clean upper line. You can make it as curvy or as straight as you want. This makeshift tool will save you time and money.