A few types of apps can help you get more from an iPhone 5:

• Camera apps: Camera+ was recommended for giving more control than the stock app, including separate focus and exposure and other shooting aids. 645 PRO MkII was also suggested if you want a more manual, camera-like interface.
• Panorama apps: For wide landscapes, a panorama app can be useful. Photosynth was specifically recommended, and some users preferred it to the iPhone 5’s built-in pano mode.
• Editing apps: Snapseed and Photoshop Express were recommended as good free options for editing on the phone.

Accessories can also help:

• Clip-on optical lenses can add capabilities such as wider views, telephoto reach, or fisheye effects. If you go this route, pay close attention to reviews, especially for image quality and how securely the lens attaches.

In general, the biggest improvements will come from apps that give you better control over focus/exposure and from using panorama tools for wide scenes. Editing apps are useful after the shot, and lens attachments can help if you specifically need a wider or longer view.