You generally have two possible routes to go. You either chose a stripe pattern that has a more or less comparable size as the pattern of the suit, or you go with a thinner one. The first route is acceptable because the pattern of the suit is somewhat complex and thus there will be no visual war between the two. This route includes the wide/medium pin stripe (if the bigger, usually, white space is similiar to the pattern block of the suit), which, in my opinion, will probably look best. The second possibility is to wear shirt with typical dress stripe, which will genrally be a safer option.