if i know all about my friend i'll remember what he/she likes. if my friend likes cars i'll buy him a car from popular collection of cars. if she is a girl and she likes to draw i'll buy her more things that coloring pencils or markers. if i know good my friend i'll buy easily somethig what she/he'll like of course. but for a succesly choice i'll book me more time be cause it's a good rule - to book(a rezerva ;din google translate) more time to buy any present