For my part I like if possible to run my campaign in phases, for example my current campaign (under construction),phase 1 will invole the party being contacted at Trobridge inn and one of there number being recalled to Orbaal, by his farthers old friend to help him fight "a 'hate' from olden times"
Nice one! "I saw the glowvurm, though, long as a hundred sheeps."
I'm used to a much looser structure in my campaigns. I have a main story arc, and I begin the campaign with an adventure very much related to it.
After the opening sequence, players are left very much to their own devices, they think. Actually, what happens is that I put three or four hooks down, and it's their choice which they bite. One of the hooks may be related to the main story arc, but it doesn't really matter if they don;t choose it. We have fun anyway.
Every once in a while, I'll introduce something related to the main story arc -- perhaps the opponent they've chosen to tackle turns out to be linked with their opponent in the main arc, or somwething like that.
Eventually things reach a crescendo.
Naturally, this technique doesn't really work with short, tightly-focused campaigns. I've no real experience of running this kind of game. One-offs or long, sprawling, play-all-day-Saturday-for-a-year games. Them's the ones I run.