Answer by Dorothy Hohl-Lorenc:
I've worn false lashes, either individual or strip lashes, daily for many years.
Let's start with strip lashes. When you're just learning to apply them, look for a lash that has a very flexible band. Because of the way each lash is attached to the band, lashes that are more dense generally have a less flexible band than more natural density (less full) lashes.
First, hold the band up against on your lid at the lashline, to see if it fits. If it's a bit too long, trim the lashes from the outer end.
For adhesive, you have a choice between one that dries clear, or one that dries dark. I prefer the clear because I think it's easier to see when it's dried to the right stage before applying the lashes than the dark adhesive, but YMMV.
False eyelash adhesive is very similar in composition to rubber cement. You may have used rubber cement at some point to glue paper to paper. It's popular because when used correctly, you can separate the glued parts without damaging them - which is exactly what you want when wearing false lashes - to remove them without damaging them OR your own lashes. Like rubber cement, lash adhesive is applied to only that which you'll want to remove later (the lashes). To get a strong - but temporary - bond, you apply the adhesive to the lash band only, let dry until it's tacky (no longer liquidy), then lay the lashes down on your lid at the lashline. When done properly, when you remove the lashes you can just gently peel them off your lid, and all the dried adhesive will remain stuck to the lash band; not your skin or your own lashes.
The mistakes I see most frequently with false lashes are applying too much adhesive and/or attempting to put the lashes in place before the glue has become sufficiently tacky. These are both very important! Using too much adhesive will mean you have to wait longer to set the lashes in place, and not waiting long enough for the glue to become tacky means the adhesive will ooze out from under the band and onto your own lashes, making the false lashes more difficult to remove without damaging your lashes and the falsies. I recommend practicing with a cheap set of lashes. Apply the adhesive in a thin line, on the band only, using a toothpick. Let it dry for 30-60 seconds, then stick the lashes down on the back of your hand.
If you've used the right amount of glue, and have let it dry to the right degree of tackiness, you should get an instant bond with no glue oozing out from under the band. The length of time it will take for the adhesive to become tacky will vary with the amount of glue you use, and the temperature and humidity in the room. As the adhesive begins to dry, you'll see it begin to turn from opaque to translucent. With practice, you'll be able to see when the glue has reached the tacky stage and it's time to apply the lashes.
Most instructions say it's easiest to apply false lashes by first adhering them to the center of your lid, then the inner and outer corners, but that never worked for me; I could never get the lashes centered the same on both eyes! So, while I was still in the learning phase, I'll place a tiny dot (using an eyeliner pencil) at the base of my lashes near the inner corner of each eye where I wanted the strip to start. Then, I'd lay down the lashes beginning at that dot at the inner corner, and work my way across the lid to the outer corner of my eye. Once the strip is laid down, I take a cotton swab and gently press down on the band from one end to the other, to ensure a tight bond.
Some people swear by the plastic gizmos that hold strip lashes in a curve while you apply the adhesive and then, when the glue has become tacky, use it to place the lashes, but those always seemed cumbersome to me. I use a pair of slant-tip tweezers to pick up the lashes (holding them near the inner corner) and maneuver them in place. Some people just use their fingers. That's one of those things that you have to practice to see which works best for you.