Driving User Adoption for SharePoint is one of the most important, but also one of the most difficult tasks that a SharePoint architect/administrator has.  You could even say that it is THE most important task when designing/deploying SharePoint.  Simply because it drives everything else.  If the deployment doesn't function correctly, then user adoption will suffer.  If it is difficult to navigate or understand, then user adoption will suffer.

Here are some key areas that I like to focus on when planning for user adoption...
<h1><strong>1. Make it Familiar</strong></h1>
In order to properly design a SharePoint deployment, you have think like an end user.  And not just any end user...YOUR end users.  Every corporate IT environment is unique.

How do your users access shared documents?
How do they access their personal documents?
How do they access reports?
How do they share ideas?

These are all key questions that need to be asked.  A survey of a portion of your users probably wouldn't hurt either.  The closer you can make accessing documents and information to the way your users are familiar with will help tremendously with user adoption!
<h1>2. Make it Functional</h1>
One of the biggest reasons for choosing SharePoint that I hear is for 'document sharing'.  But, why use SharePoint?  Why not just use a network share or maybe even a cloud based sharing solution?  These are common questions and they are completely understandable.  However, it shows a lack of understanding of the key enterprise features that SharePoint offers.  Here are some key features that users should be well trained on prior to deployment so they fully understand how to use the tool...

Versioning
Content Types and Document Templates
Enterprise Search
Workflows