Some of my friends, I always take suggestions from, cuz they read the same stuff as me, but other friends I just think "How do you not fall asleep halfway through the BLURB?? " The school librarian knows what I like to read as well (seeing as she's the one who always has to check the book out hehe)
For my own choices, I just look at the titles and the look of the spine of the book, then if it looks good I pull it out and look at the blurb and cover. Then if it still looks good I tend to read the first page on the way to take it out