I'm with bloodymage on this. I don't really plan a story. I just plan a world.
For instance, I'll start with a village. Where is the village? In the foothills of the mountains, on the bank of a swift and cold river. In fact, let's call this village Coldstream. Why is Coldstream here? Because the trees in the area provide an excellent quality of hardwood and a tasty nut. Heck, let's say they're walnut trees. So Coldstream is populated by loggers, but the inhabitants also gather nuts, which they consume themselves, and also trade for other goods. And let's say that the residents also hunt game, both large and small, to provide themselves with meat, hide and bone.
Now, what sort of services should we have in Coldstream? We need a blacksmith (expert 2) who specializes in making axes and other tools the loggers need. He also provides arrowheads for the hunters, as well as metal implements such as pots and pans for the community. We also need a tanner (expert 1), since hides will be relatively abundant. You can't trade stinky raw hides. Well, you could, but do you really want to store them? Blech. We also need a temple, probably to a nature god, so there's a priest and maybe a few acolytes. (Cleric 2 and some first level adepts.) Because this is D&D, we need a tavern. Throw in a handful of trappers, hunters, loggers and the like, and come up with names for them. If you've got a village map (check the WotC website) it's all good.
Next step, what sort of problems does the village of Coldstream have? Did someone's heirloom sword get stolen? Has the blacksmith's son gone missing? Is one of the acolytes acting funny? Is the best hunter feuding with the priest? Is the caravan late? Has a dire boar and his sow wandered into the region, scaring all the deer away? Are kobalds coming down from the mountains all of a sudden? Pick a few of these, and you have several adventure hooks.
Now, let's pick 4 of those.
1. The blacksmith's son is missing.
2. The caravan is late.
3. Dire boars.
4. Kobolds.
You can tie these all together if you like. Maybe the blacksmith's son went to gather walnuts and was killed by the dire boar. The dire boar has wandered into the area because the kobolds have pushed it out of its usual habitat higher up in the mountains. The caravan is late because the kobolds have blocked the road with a rockslide, unbeknownst to the inhabitants of Coldstream. The kobolds are coming down from the mountains because they uncovered some nameless horror in their mountain lair and it has mind controlled their shaman/leader.
I could go on, but you get the drift. The PCs can choose to investigate any of these plot hooks, or they can wander off and do something else. Of course, if they wander to the west, they'll find the blocked road and a bunch of kobolds. If they wander to the east, well, you'll just have to come up with something for them to find in that direction.