Which size to choose?
3-4mm - good for small BJD's and 12" fashion dolls
4-5mm - good for dolls with 14mm or smaller eyes and 16" fashion dolls
5-7mm - good for dolls with 14mm or larger eyes and larger fashion dolls
How to apply?
Here is a wonderful tutorial by Laurie Lenz of Angels Doll Studio:
Lashing Out! Eyelash Tutorial
Please note - if you use the eyelash lengths recommended above, you probably won't have to trim them.