I've recently started running a campaign in the Pathfinder setting for my family. I'm hoping that we'll eventually get to the point where we can play on a regular basis, but life has been hectic so far!
What campaign setting are you using - an existing one, or one that you're making yourself? From my experience, there is an abundance of adventures on-line that you can find (some better than others), so if you're making your own campaign, it can be easy to shoehorn ones you like into the ongoing narrative.
One of the biggest pieces of advice I can give is this - let the players shape the world around them. In one of the longest campaigns I ran, I allowed the players to determine the outcome of the adventures, rather than stick rigidly with the script. It ended up changing things that I had planned, but it worked out for the better. Since the players became emotionally involved in the world they helped to create, it allowed them to become more immersed in what was happening, and filled them with an eagerness to come back every time we played.
There have to be limits, of course. You shouldn't allow your players to roll up a half-dragon lawful good paladin with a +5 holy avenger at level 1, for example.
But listen to your players, shape the adventure(s) to what they would like to see, and go with the flow.
"All the miseries and evils which men suffer from vice, crime, ambition, injustice, oppression, slavery, and war, proceed from their despising or neglecting the precepts contained in the Bible." -- Noah Webster
My blog: Writing from Idaho