ماذا أفعل لأقدم النصح لصديقتي المقربة بارتداء الحجاب؟

You must teach your friend the obligation of hijab, and warn her against tabarruj (immodest display), which is considered one of the major sins. It is recommended to gift her booklets and tapes about the virtue of chastity and hijab, and to guide her towards righteous company. You should also supplicate extensively for her guidance, while exercising wisdom, patience, and not despairing in inviting her, seeking Allah's help and showing kindness towards her. It must be reminded that the Shar'i (Islamic legal) dress has specific conditions and characteristics.