The Traditional Approach
It is our experience that the standard procedure of hiring an architect separately from your builder may result in several issues. If this is the route that you prefer, make sure you know both the architect and builder, and that they are both familiar with your budget before you get started.
Know their capabilities and that they can work together to communicate well with you and with themselves. Without this rare builder/architect relationship you may find that your design may be flawed by finding that you have become the middle-man between your architect and builder. By over-building the hierarchy, it creates unnecessary costs because the architect may question the builders skill, may design to accommodate the customer's desires without consideration for their budget, or job site delays when builder is waiting for architect to make revisions.