I am a sorta newbie DM (been playing for about 5 months) and I have a couple dungeons. So is that all I need to make a campaign? I have about 6-8 friends that I play with every week, but they are mostly newbies too. Any help?
While you're off to a good start, as a newbie DM, I would recommend that you work first on your skills as a DM. Run a few modules as one offs. Get practiced in how to tie chapters together into a coherent module first. Once you get a feel for how to start tying elements of a story together, you'll have a much better basis on which to move on to a larger world.
From there you can move onward. Take three or four of the modules you've run. Come up with ways that those individual modules could be related to each other. Think about the plots. Is there a way that you can tie the plots together in a way that would support an overarching storyline? Is there a common theme that you can derive from them.
Once you can start seeing ways of tying individual modules together into a coherent background story, you'll have a much better idea of how to create a world and an overarching story that will tie that world together.
I think the problem that a lot of DMs run into early on is in finding a way to tie together the various modules that a group will play into a single storyline. Some groups are fine with that, just enjoying playing each module as it comes as a separate "world". Other groups, like the one I participate in, have been playing in single world for about 15 years now. And throughout that entire time we've run many modules all tied together into a single, overriding plotline.
So, in short, start small and work your way up. When you reach the point of starting to create your world, begin with a plot. What is the story that will tie your campaign together. It doesn't have be big and detailed. A short paragraph will do to start with.
Then begin with the beginning. Flesh out the town where the campaign will start. Start with a small village, one that's easy for you to map out and create a few major NPCs. Nothing complex.
From there figure out what your initial campaign module will be. What is the initial story that will tie your campaign together? And how will your individual player's come together? Let your players decide as much of their backgrounds as possible, but they'll all need a reason to be there. While an individual game session or module is easy to say "You look trustworthy, come with us...", if you're going with a campaign, there is a much greater need for a story that ties them together somehow. If you can get that, you will be well on your way to making your gaming sessions into a real campaign.
To make a campaign, you need only continuing characters.
To make a good campaign, you need additional continuity... of setting, of story.
Many campaigns use a map as the basis, putting various adventures' locations on the map. Most do well to have a mix of dungeon and non-dungeon adventures, as well. Further, travel to and from a dungeon can up the effective level of the dungeon by a level or two, by burning resources getting there, but the exact effects vary by game and edition...
If you prefer not to use a campaign map (and they aren't essential, but are useful), simply come up with ways to link the dungeons and explain why the PC's aren't threatened en route to/from the dungeons.
One of my favorite published campaigns has two adventures in one city - one in the city proper with mostly social encounters, and one dungeon crawl through the sewers. (It's for WFRP - The Enemy Within campaign.)
Another excellent one (AD&D's G1-G2-G3-D1-D2-D3-Q1 campaign) puts each module just a little bit further on - they flow together pretty well. So you might consider dungeons that lead through some barrier, leading to a new "base" - village or town - from which several more dungeons open up. One of which then leads on to yet another new base.
Likewise, a campaign map need not be graphical. It can be a "subway style" map, or even a text-only map like such:
Also, don't be afraid to reuse a dungeon, perhaps toned down following the last foray, perhaps entirely repopulated, or perhaps a duplicate. One campaign I ran used the same module (B2 Little Keep on the Borderlands) 4 times... as 4 different keeps of a standard pattern, with minor variations of inhabitants. (Pick equivalent monsters, and every time it says Ork, use Skeleton or kobold, for example.
The most important element to a good campaign is that it keep the players interested. My experience is that a sense of place is helpful, as are continuing story elements, and having a good time with each session and adventure.
If you're playing with a group of friends every week, in many respects you already have a campaign.
All you really need for a campaign, in my opinion, is continuity -- continuity of setting, characters, and history.
Now, if you want to create a campaign world, then you need some blank paper and imagination. There are tons of websites out there that talk about creating a fun world. One of the best to look at is the online archives of Ray Winninger's column Dungeoncraft, from Dragon magazine.