Before you start to apply, measure the length of the false lash to make sure it fits your eye shape. This will avoid the corner drooping or worse, the end poking into your eye. If the strip needs be shortened, cut the outer edge completely off with small nail scissors.
Take both edges of the false lash and bend them in to create a C shape and hold for a couple of seconds. That's the best way to take out the straightness and ensure it molds to our curved eye shape and stays put without the corners lifting up. Just this alone will make the rest of the process effortless.
Apply a high quality glue such as Duolash for long lasting results, not the glue that comes with the pack! If you have a steady hand, you can squeeze straight from the tube onto the strip. Or an easier trick is to put glue on a cotton swab or a toothpick and glide it across the lash strip. Make sure to be generous at both the inner and outer corner so the glue won't unstick when you blink.
Wait 10 seconds or so for the glue to become more tactile and sticky before placing onto your own lash line. Try blowing on the glue or gently wave the lash around in the air to speed this up. This is the best way to keep the strip from slipping around while you're trying to line it up properly.
Apply the lash to the base of your natural lash line on top of your actual lashes, not on the eyelid at all. The glue dries clear so don't worry if it gets messy.
Apply mascara last so you can integrate the natural lashes with the false ones, making sure they mesh into each other.
If you see a gap showing on the eyelid skin between your own lashes and the false ones, don't pull off the strip and start again. You can just fill in the gap with either black liquid liner or eyeshadow to hide it.
Always remove false lashes before taking off rest of your eye makeup. First pre soften the glue with a cotton swab that's been soaked in an oily makeup remover [try Lancôme or L'Oréal]. Use a dabbing motion along the lash line. This loosens the glue up and breaks down the strength and stickiness. While your eyes are open, take hold of the false lashes at tips of the outer corner. Then close your eyes and slowly, slowly peel them away from your own lashes, working from outer to inner corner—towards the nose.