What are you using to glue them with?
My advice is to take the lash in very fine tweezers & nip your thumb & first finger over the gummy glue that was holding them in the plastic case...this should gently peel away from the lash.
Use Aileens tacky glue..its thick & dries clear. Use a cocktail stick & just get a tiny blob of glue on the end....carefully run it along the the rim of the eye where you need the lash to sit, leave it for a couple of mins, then run another thin line using the cocktailstick along the side of the lash you need to fit into the socket.
Using tweezers to hold the lash & a clean cocktail stick in the other hand, gently place the lash & push into position with the coctail stick. As long as you wait before trying to place the lash the tacky glue will hold it in place.
Once the lash is in position just gently push it with the cocktail stick to squeeze out any surplus glue...you can then use a cocktail stick to 'mop' up the extra glue, as it becomes more tacky it will gather on the tip of the cocktail stick.
After a few mins you can clean up any excess glue on the eyeball using a dampend cotton bud, (not very hygenic-but I touch it on my tongue, so it doesnt get overly wet!)
Dont get stressy about it....stay calm, like a lot of things it will come with practice, one day it will just fall into place & seem the most natural thing you have ever done!
Hope that helps
jen x