The only preparation recommended is that you wear no eye makeup to your service appointment as it interferes with the adhesives. This will save your Lash Artist time having to clean your lashes a few times to make sure that your lashes are clean and and ready to lash. which means that your Lash Artist can have extra time to apply extra lashes for you.
Try to avoid wearing any mascara a few good days before your lash extension appointments, because there is usually a trace of mascara is left although it can not be seen.
For best retention the lash extension need to be applied directly onto your natural lash, not your invisible make up or mascara.