I had been working as consultant for about two months already. One interesting thing I found in those days regarding how to use consultant effectively.
1. Hire technical expert as technical leader, so other team members can learn from him. This way is better than hiring a trainer. This works very well if this company run into a new technical area.
2. Hire Junior consultants doing heavy load and lower technical tasks. Also those works are perfect for outsourcing.
3. Team members should include both full-time and contractors. A team contains only contractors will face long term maintainability issues in the long run. Some one in the team should audit the quality.
"Knowledge can be conveyed, but wisdom is only earned by experience of trying"