Yeah I'll be doing a lot of posts about fake eyelashes, but I hope no one cares :P
There's been a big boom within the gyaru fashion magazines about making "custom lashes", which is basically putting pieces and parts of different lashes to make their own custom look. It's a great way to use lashes if they're on the verge of being thrown away or just to get creative!
Darkness Eyelashes or by buying bulk sets of eyelashes off of eBay.
I didn't really do much except just literally glue them together. However if you do this, remember to bend your lashes a ton before applying them on! They'll stay straight and it'll be hard to bend them into place otherwise.
The preferred method on doing custom methods is gluing the layers separately onto your eye with tweezers, but for people with no time (or just finding shortcuts/lazy like me) it's easier to find a way to put them on easily with just your fingers.
I might do this more often, especially the lashes I use for everyday use that start to get ratty on me. :)