Pull up a bean bag chair and let's get started. Saturdays are going to be dedicated to discussions about building your own homebrew AD&D campaign. This advice can easily be applied to Swords and Wizardry, OSRIC, D&D Basic or 2nd Edition D&D and probably 3.5 as well.
So the first thing you need to consider is whether or not you have the patience and time to create your own homebrew campaign. Back in the early 1980's a great many DM's invested the energy into their own worlds because many of us were younger with more spare time to do so. Over the years DM's found themselves with less free time and a great many more high production and detailed out of the box campaigns to run their games in and homebrew campaign building became more and more of a rarity.
With the coming of the OSR homebrew campaign creation has come back in a fairly significant manner. Part of this trend comes out of an interest in self publishing and I often wonder how many of the new homebrew campaign creators actually run players through their own material but this is not a critique of current homebrew campaign building.
The first thing you want to do is decide a few themes that you want to run throughout your homebrew campaign. Many of these have been done before but your focus needs to be what is fun for you to write and draw and not so much worrying about what everyone else is doing or has done. What do you think your players will enjoy? What will you enjoy? You are the one that is going to have to labor over this creation for hours and hours, weeks and weeks, months and months and possibly years and years while you run it for your friends. It would be a good idea to write about things that you find exciting and entertaining as your personal enjoyment will help keep you going.
In my Kingdoms Chimerical campaign one of the themes I wanted to introduce was the concept of the World as Dungeon. This is not to be confused with Dungeon World where the entire world is one big dungeon. In Kingdoms Chimerical I wanted to really bring back an early AD&D feeling of exploration not only when inside of a dungeon but also while traveling around the campaign city and in the wilderness. I found that some of the more modern and pretty cartography conventions I had gotten used to throughout my later gaming career got in the way of this sense of exploration. What it required is a foundation approach where I was making my practical DM maps on graph paper and by this I mean absolutely everything, wilderness, cities, villages, everything was mapped in the same sort of semi abstracted manner found in a dungeon map.
I can't really take credit for using graph paper and a maze like approach to wilderness maps. This was demonstrated to several of us as players at Gary Con One by Frank Metzer...I'm pretty sure it was him. Sorry I am getting older and can't always remember the specifics as clearly as I would like. Metzer noticed I was really interested on how he was running the wilderness crawl we were on and during a break to some time out to let me see the grid map he was using. He explained that during the early days that Gygax and some of the others working on AD&D thought that perhaps wilderness / overland maps would all be done on graph paper with the terrain drawn into a sort of maze where hills or deep forest would represent a more difficult and sometimes much more difficult "level" of the wilderness. So the encounters you might find while exploring a valley would be first and second level encounters while moving on into the hills might have you encounter a vampire...which is exactly what happened to us when we tried to take a shortcut out of the valleys where we were searching and over the hills to our destination.
That was a big lightbulb going on moment for me. Let the players understand the grid nature of the region they are exploring so they can travel a mile and ask the question, ok what does the terrain look like now to the West, to the North, to the South. We want to go West but the forest gets deeper and we already know that deep forests tend to be quite dangerous (monster encounter level four). We don't want to die. We decide to skirt the deep forest at our current level and head North into terrain we already feel we can probably handle.
Bingo. Wilderness travel and exploration is suddenly new and vibrant and interesting again. Players need to be concerned about supplies. Unless they always stick to the roads and unless you as the DM always have roads leading to exactly where they need to travel (just don't make roads that go everywhere...force them to have to overland travel to get to the remote dungeon or wizard tower or whatever) they are going to have to map it out on graph paper and navigate a maze of wilderness you've created...i.e. EXPLORATION...to find their way to the destination.
Your wilderness maps won't be as pretty. Mine certainly are not. I can hand draw a really nice map. I'm a good fantasy cartographer...or at least I don't suck. I've abandoned pretty maps for maps that function properly in the AD&D game.
In the same fashion my city maps are now set on a grid. Each space is about a three block square of the city. Each block is coded as a different type of neighborhood. Slums, Merchant, Crafting, Wizarding, Temple, Barracks, Noble...etc... Each type has its own encounter tables created in a level system similar to the wilderness idea. Players moving around in the city now need to get out a map of graph paper and map it out. I just use colored pencils to color code the different neighborhoods. Red is slums. Blue is merchants and so on. The players pretty quickly discover there are certain neighborhoods that are much more dangerous than others. This can be through encounters with thugs but also say the Noble District while not a place where you are going to get mugged will have level five encounter guards keeping a close eye on everything. Try to break in somewhere in the noble district and the monsters...guards you will be faced with are going to be really dangerous. Players quickly learn that they have to think about what they are doing and plan a little more. There are dangerous people and areas of the city and wilderness they want to avoid.
This all brings back the mood of an early AD&D campaign in a big way, something that I believe has slowly been leeched out of the game in an accidental fashion for a good many years.