1. Manage your expectations. Agencies invest a lot of time and money in pitches so clients need to bear in mind that the process can sometimes last several days. Some pitches I've been involved in have suffered from clients turning up late, wanting to move things along quickly, or by other interruptions. The pitch process is not something that clients can duck in and out of. It's also not uncommon for the equipment clients provide to malfunction, so it's a good idea to ensure this doesn't happen.
2. Don't see too many agencies. Ideally you want no more than three, perhaps up to four agencies involved in the actual pitch process. Engage with any more and it will cost you time and money. We draw up 'long lists' that typically have between 12 and 20 agencies or, if the brief is quite niche, fewer than 10. We then prepare a report for the client, who can request more details if necessary or arrange a chemistry meeting. This has resulted in some clients making a decision then and there.
3. Agencies like questions. It's a sign of engagement so don't hold back. You'll learn a lot more about the agency this way. Preparing questions is also useful as it can help you identify any areas where you might or might not need further information. Feedback too is vital - don't be shy. Agencies are used to this so it won't shock them, provided you can give your view in a constructive and considerate manner. It's equally important for clients to ensure that they are clear from the outset about what information can and can't be revealed to agencies.
4. Offer to pay a nominal amount. Clients are becoming more considerate of the time and money that agencies invest in pitching and some are now offering to pay a fee towards the process - it tends to be a minimum of £5,000. A small, final but important point: have some drinks available. I've attended some pitches where there has been no tea, coffee or water.