Any design as plant-heavy as the cottage garden style can profit from some well-placed hardscape features. I mentioned using arbors when designing a cottage garden on Page 2, but don't stop there! A gated picket fence covered with morning glory vines is useful either as a backdrop or as a foreground for tall flowers in a cottage garden design. Just remember that cottage gardens are supposed to invoke a feeling of hominess, if not rusticity. Plan your hardscape accordingly, avoiding ultra-modern styles. If you can't find a fence style that is right for your cottage garden while complementing your house, substitute a short hedge for a fence, perhaps a holly.
I offer a full article on fence line landscaping if you wish to pursue that topic further (outside the context of cottage gardens, specifically).
Along the same lines, informal pathways, perhaps even stepping stones, are preferable to formal walkways. Even if you have to compromise on selection of pathway material so that it is in keeping with your house style, make sure that the pathway curves its way in and out between your trees, hardscape and planting beds, so that viewers can't take in everything all at once. A cottage garden should be full of surprises. Keep the viewer guessing what might be revealed around the next bend in the pathway.
It's important to achieve a sense of privacy in a cottage garden. But as mentioned earlier, not just any privacy will do. The idea is to re-create the sense of serene privacy felt in a bucolic setting. So a vinyl fence just won't do here as a privacy screen: the material is too modern. And while a picket fence is in keeping with the cottage garden style and has its uses (see above), it isn't tall enough to offer privacy. If you can't find suitable hardscaping material for screening, remember that "privacy fence" needn't be taken literally -- a "living wall" is an option.