It is so important to be conscious of the attachment between the extension and the natural lash - remember a good attachment area is between 2-4mm, compared to a poor attachment, which is anything below 1mm, meaning that your pretty fan is likely to brush off only a couple of days later. You also need to be aware of placement, making sure the extension is angled 90 degrees from the eyelid - incorrect placement may result in stickies where a single lash will bond with the neighbour and cause not only poor retention, but damage to the natural lashes. Finally bear in mind that thicker lashes may need a little more glue to wrap around the natural lash and create that strong bond, so pay attention to the amount of glue you are picking up, as it can be different for each person