A cottage tends to be a small dwelling, which means any cottage sofa you choose will first and foremost need to fit well in the space. Take accurate measurements of the living space to help determine how large of a cottage sofa you can fit there, and think carefully about how many people are likely to use the sofa at once. If only one or two people will use the unit at any given time, a two-person sofa may be appropriate for the space, but if your family is larger or you expect more guests, look for a three-person sofa or larger.
Once you have determined what size of cottage sofa you need for your space, think about the materials you would like the unit to be made from. Remember that the materials can raise the cost of the unit quickly, especially if you are looking for premium materials such as leather. If you want the look of leather but don't want to pay the price, you may be able to get a faux-leather cottage sofa that looks similar to leather but is far less expensive. Try to choose a sofa that is consistent with the existing aesthetic of the cottage; if the sofa already has mission-style furniture, for example, a Victorian style couch may not fit well.
Think carefully about who will be using the cottage sofa. If, for example, kids will be on the couch regularly, you may want to consider a sofa made with durable, stain-resistant materials that can be cleaned easily. If the sofa is more for aesthetic value than functionality, you may consider finer materials such as satin, silk, or leather. Remember, however, that some higher end materials will require more maintenance, which means you will have to spend time and money cleaning or otherwise caring for the unit.
If you will be hosting guests regularly, and if space is at a premium, consider a fold-out sleeper couch. Such sofas feature fold-out beds that can be concealed beneath the cushions when not in use. These sofas tend to be heavier and more expensive than other models, but they are exceptionally convenient because they can be folded in on themselves when not in use, saving valuable space. When sleeping accommodations are necessary, the couch can be folded out to accommodate sleeping, thereby preventing the need for a separate bed that will otherwise need to be stored somewhere else in the cottage.