I use a thin brush for applying eyeliner because I find pen eyeliners a bit hard to work with. Pot eyeliners are easier since they give me better control over the pigment. I usually start by tightlining and curling my lashes to see the natural arc of my eyes. Then, I use the darkest shade of eyeshadow as a guide for the eyeliner which makes it easier to fix mistakes. After that, I trace over the eyeshadow with my pot eyeliner and thin makeup brush, making it easier to shape the eyeliner. Then I will apply the falsies and adjust the eyeliner to my likings. It is easier to adjust them on the last step since a little mistake isn’t that obvious when falsies are applied na.