1. New technology
This does not mean implement every possible new feature or design methodology, but that enough knowledge is gained so that the most appropriate decisions are taken when building the foundation of a solution. Existing functionality may already be offered as part of a 3rd party system or service which may eliminate the need for development while providing a cost effective, managed, secure and scalable option.
2. High cohesion and low coupling.
A design in which functionally can be separated with relative ease into components performing specific tasks will enable a far greater flexibly. The ability to replace or adapt parts of an application will allow for quicker re-architecture and for 3rd party solutions to be incorporated.
The ability to test in an automated and repeatable manner the full scope of the design is absolutely critical, as without it there is an increase in both unknowns and risk.
The limitations of physical resource will impact the design. Inconsistent network communication or high latency links for example will remove architectures that perform high volume or synchronous transactions.
As design complexity increases there is often a point where it becomes subject to financial restrictions that make further development or expansion no longer viable.
It is important to understand the technology being implemented and how it can be used. A design that pushes the limits of a technology can work in many cases, but thought must be given to how far a design is pushed and the restrictions that are present. For example, real time synchronisation across a global infrastructure may quickly hit limitations.
A design may achieve many of the core requirements of a business in redundancy and high availability by an infrastructure which is globally dispersed, but then this may be impracticable because of legal requirements to have data hosted geographical locations.
Deciding how a design will scale is almost as important in many ways as the functional ability of the solution. A solution design with little thought for scalability usually relies on vertical scale-up strategy that can very quickly hit both resource and financial limitations. A horizontal scale-out solution however which incorporates sharding or data partitioning will scale to far higher levels as the shared load is far easy to scale.
A system that may seem incredibly secure today will tomorrow be obsolete as technology and research is undertaken. It is important to make sure that security is implemented at a level that meets the requirements, but it is prudent to exceed the requirement up until the point where it becomes impossible in terms of resource. A secure system is always most vulnerable at the weakest point and implementing minimal security only guarantees that.
Plan how to design the platform using an iterative approach making sure goals are achievable and well thought out. A plan should be based on what needs to be achieved and not what time allows. If a plan is shaped by additional factors these should be highlighted and risks identified.