[Ned Flanders]

Most good measures to running a solid and fun campaign have already been pointed out. I have a couple of things to add although it's been almost ten years since I've DM'ed or played any PnP DnD.

I ran campaigns for about five years in the world of the Forgotten Realms and before that for about four years in the world of krynn. One element that always got players really into things was to introduce specific characters and locales they may have encountered in reading novels of the various realms in which we played. Given something the players could relate to allowed them to really touch base with the adventures we were creating.

Second, I'd recommend at all points during a campaign, preferably each session, to find the opportunities for long breaks which serve a dual purpose:

1. Give the players a break to munch, go to the can, chat about things, whatever, it's healthy and
2. During this time, take the opportunity to do some DMing one on one. A lot of times, if something happens you only intend for one player to hear, it comes in the form of passed notes. Use these long breaks to expound on some of this 'secret info' intended for one character by playing one on one. I've often found it allows the player to get more into his character and perhaps even find a little identity for the character. This often assisted in group play as well as with the entire group around sometimes it becomes difficult to develop individuality with each PC.

Alas, I sure miss running campaigns.