Some glues used are Aleene's Fast Grab Tacky Glue, Aleene's Quick Dry Tacky Glue, Tombo Mono Aqua, various CA glues (super glue, crazy glue, &ca.)
It helps to put a little glue on a scrap piece of cardstock or some other holder and use a toothpick to apply to the area to be glued. Wooden toothpicks are OK, a plastic one is better.