It comes from experience...personally, I think it's easier to see with the adhesive that dries clear, as opposed to the dark one. When it's wet, it's opaque. When it's completely dry, it's clear. The "tacky" stage is when the adhesive is translucent. You can always practice with an old pair of lashes on the back of your hand. Apply the adhesive, wait about 30 seconds. Apply to the back of your hand. Are you getting an immediate bond? Is excess adhesive oozing out from under the band? If so, wait until the adhesive dries completely, peel it off the band, and try again - this time, using a bit less adhesive and waiting a bit longer before you apply the lashes to the back of your hand.
I didn't mean to imply if you follow Zadidoll's removal suggestions you will rip out your natural lashes.
But, that method is more time-consuming than if you're simply able to gently peel the lashes off, which you can do if you've applied them correctly to begin with (correct amount of adhesive, and allowing it to dry to tacky stage before laying the lashes down on your eyelid).
Practice makes perfect. I wear false lashes every day (due to a little accident I had with a sunlamp when I was a teenager - nobody told me to wear googles... I ended up burning my eyelids and apparently damaged the lash follicles...causing sections of my lashes to fall out, never to grow again).
BTW, really good "practice" lashes are the "Dramatic" lashes made by E.L.F. 1.00 a pair! They have a nice flexible band (which helps make them easier to apply) and while the lashes are long, they aren't terribly dense and I think, look pretty natural. I usually get 5-6 wears out of one pair if I take good care of them....
I'm wearing them in my avatar pic (and if my bangs weren't so darn long, you might even be able to see them!)