Lay out your design first before gluing anything, just to get an idea of how it would look. When you got an idea of where the placement would be,remove all the studs but one to mark the "start." Using a ruler, drew a line lightly with a pencil to use as a guide. Time to glue!
Put a small dot of glue directly onto the case, where you'd like the stud to go. Quickly place the stud on top of the glue. Using a manicure stick get the stud in the correct position as quickly as possible.
In order to maintain a straight line of studs, it's best to take your time. Once you have all your studs glued, leave the case alone! No touching for at least 24 hours! And just let the glue dry completely so they studs would hold as long as possible.