totally punk rawk!
i've found that the best way is to just do one guiding line with chalk and line the rest of the studs up against each other so that they fit well together, so even if you fuck up your line, at least they'll look well put together. but that's not very punk rock. if your a TRU PUNK!!! you'll down a 40 while listening to a global threat or anal cunt and do it while sitting in a gutter yelling obscenities at the cops. if you're not a poseur.
as for keeping them on, the best way really is to make sure the prongs are bent inwards. you can always apply a bit of hot glue, but that can get uncomfortable if the glue mounds and it will feel like you're wearing the studs on the inside of your jacket.
final summation: sniff glue out of bags.