Lessons from building the "Raiders of Oakhurst" series -- not all of which is 4E-specific advice:
- Ignore scale when you build rooms. A room 60' on a side is unrealistic in most construction, but makes for a great room to have a fantastic mobile combat. Learn to balance realism with fun gameplay.
- Make rooms and corridors bigger than you are used to -- or if you make them the same size, understand that you will be significantly limiting PC abilities.
- Challenge and encourage movement by adding more interesting terrain -- stairs, tables to climb over, pits to jump, rope bridges to cross, areas that provide combat advantage if used correctly, different height terrain, etc.
- Consider more integrated and linked encounter areas. Instead of a single room as an encounter, link the monsters in several areas into one big encounter that causes them to join in in a realistic manner as the "alarm" is raised, or the sound of fighting reaches them. Multiple rooms then provide a complex level appropriate encounter.
- Combine complementary monsters. For example, a brute, an artillery, and two skirmishers provide a range of tactical options for the foes and for players to counter.
- Provide a range of challenges. On average for 1st level, 100XP per character is a "normal" difficulty encounter -- but put a few that are below normal, and a few that are above, with the occasional solo or elite to provide a different challenge. That means a lot of monsters are available, as a challenging but surviveable encounter for 5 level 1 PCs could be up to 700XP of monsters or thereabouts.
- Remember minions. They are a great way to add "volume" to a 1st level encounter without making it overwhelming to PCs. Nothing says cinematic like a horde of zombie minions ...
- Consider adding "trap effects" to make encounters more interesting ... caltrops, rolling boulders, pits or fire you can push someone into, etc.
- Pace encounters. Provide a mix of skill challenges, combat, and roleplaying encounters to break up the sequence and ensure the adventure isn't a grind of one combat sequence after another.
- Enable player choice. Ideally, there should always be two (or more) viable choices available that are more than "go forward or go back". For example, they can go right and fight through undead before raching the bad guy's lair, or go left and face an og re to get there. When facing the ogre, they can fight or negotiate, etc.
- Be careful about single-point failures ... for example, the one door the PCs must pass through to negotiate the adventure, but it's locked and there is only one way to get through it and they missed that. You can use these sorts of bottlenecks, but if so, either make them easily manageable, provide lots of hints as to how they work, or provide multiple ways to bypass them.
- Don't forget that everything you place should have a purpose within the adventure's overall ecology -- even if that purpose is to impart the message that "some things are bigger that you are, so step softly". If there is a room of kobolds followed by a room of hobgoblins, why are both there? What is their relationship?
- Add history and ecology. Where do the monsters get their food from? Water? How long have they been there, and why? Step back from the overall picture and ask if it makes sense and if you can imagine creatures living like that -- it will help your creation seem more believeable.
- If this is part of a larger adventure or campaign, leave a few mysteries for later. They could be strange references to past history, maps to unknown places, an odd magic place they just can't negotiate yet, etc. If you can turn one of the foes into a recurringn villain, great -- just don't steal victory from the PC's hands via dues ex machina to pull it off. It's better for a planned recurring villain to die untimely at the PCs hands than to undermine good play with DM fiat.
- Add a few memorable personalities to spice up the adventure. He isn't just a kobold, he's Ichio-Ichi the skirmisher, with a scar over his left eye and a penchant for talking in the third person.
- Add dungeon dressing. Sights, sounds, smells .... If you can, tie things into the adventure or others that you have in mind, as you never know when a new hook might come in handy.
- Don't get so concerned with mechanical minutia that you forget to take a step back and look at the big picture. No one is checking your work except your players, and the most important thing is that they have fun!
