1. Get Advice. Just make sure its from independent experts that have no axe to grind when it comes to platform, storage, and software vendor choice. And ensure your advisors have proven track records!
2. Dont just throw money at the problem. Make sure you thoroughly understand what you wish to achieve -- not simply from a technical standpoint but also considering the business demands that are driving those technical changes. Sticking a multimillion-dollar EMC Symmetrix system in to do file sharing is probably overkill.
3. Calculate current Total Cost of Ownership (TCO). A primary motivator for a change in storage strategy is to reduce costs. However, very few people establish what their current TCO is and therefore have no fiscal barometer to either justify new investment or measure the success of the new project.
4. Make sure your new TCO model is lower than your old one. Apparently, many companies have been caught out on this one.
5. Avoid finger in the air assumptions. Everyone wants "bigger and faster," but where is it best applied and how big does it need to be? By understanding exactly who is using what capacity, where, when, and how, you can design a scaleable solution from an informed position based on fact rather than assumption.