Learn about problems early on. It is easier to persuade a client to revise a plan early on than when it's in full swing. Learn the business. One of the values of an in-house lawyer is to understand a business and its legal principles. Get to the point.
Nothing upsets a client more than an analysis of a problem with no answers.
Wander the corridors. Valuable meetings can be impromptu. Avoid memos, communicate orally - don't be a bureaucrat. Integrity is crucial. Respect confidences and be honest and fair with clients and opponents.