Here are a few quick tips to examine your existing Code to identify reuse candidates:

• Introduce Factory or Builder instead of repetitive boiler-plate code when constructing key objects. Several benefits: makes it easy to refactor and evolve how underlying objects are stitched together, makes it easy to write more intention revealing code, and very relevant / convenient when writing automated tests
• Clarify functional behavior and tease out non-functional logic – look at how functional logic is implemented across your codebase. Do multiple projects share a common set of domain assets – objects, rules, services, and the like? if not, look for areas where functional logic is tightly bound to non-functional aspects like fine-grained metrics capture, exception handling, retry / timeout handling, etc.
• Public API that needs to be accessed across platforms / devices are strong reuse candidates – for instance, are there functional APIs that don’t have a remote interface (e.g. a plain Java implementation without an appropriate REST-ful web service resource)? Do you need functionality to be made available across multiple devices with varying User Interface semantics? If so, look to carve the shared logic out into a service that can be accessed from multiple devices / integration points