When clear straps catch the light, they show just as much as any other bra strap.
I have not ever seen those little straps that Mrsleah mentions, they sound like they might be a help. Breast petals...hmm...sounds intriguing.
I've seen women who had really pretty scalloped, lacey bra straps that are obviously being shown purposely under tanktop straps.
I get the fashion drift, but I just can't go there, and it is too young a look for me anyway.