This is a basic idea, I'm not giving advice specifically on what to build. Â If you have questions, feel free to comment. Â I should get back to you fairly quickly.
1. Â Plan or not to plan?
This is completely up to the reader. Â Are you a planning in advance type of person? Â Or are you a person who hates planning of any kind? Â I personally do not plan my adventure maps. Â I simply build. Â And I recommend just building, if your buildings look good, you can build a pretty neat story. Â Build what you like, do you like modern minecraft buildings? Medieval buildings (my personal favorite!)? Ancient buildings (like B.C.)? Â CompletelyÂ your choice.
You NEED to be ok at knowing how to use redstone. Â You don't NEED to be a pro at using redstone. Â I am not by any means an awesome redstone builder. Â Know how to use command blocks. Â They help a LOT! Â Make some of your adventures and challenges with redstone, don't make 100% of your map running on redstone, but definitely use it as needed. Â Too much redstone can be a little annoying.
3. Command Blocks
Make villagers speak by button a button near one, and using /say. Â Make use of /spawnpoint x y z.
Remember that /tp @p could work as a spawnpoint system too. Â You could make items spawn at odd times in a player's inventory by /give @p. Â You could make these odd items even more mysterious by adding a /say command along with the spawned item. Â Just USE command blocks. I recommend using them!
Have plenty of action in your map. Â I really don't recommend making a map that uses peaceful mode. Â It's just boring. Â Mobs add a feeling of suspense. Â But don't go COMPLETELY OVERBOARD with your mob spawning. Â Make the player die a few times ;D. Â Or maybe more than a few.
Don't give the player too many items (not the mod lol), but literally, if they get an overload of items it isn't as fun. Â Tossing out items that aren't needed isn't fun for anyone. Â And don't give out O.P. items at the start. Â For example, don't give out diamond stuff at theÂ beginning, start out with basic stuff (stone & wood) and work your way up. Â If you give out diamond stuff early on, you may need enchantments Â so it doesn't get boring.
5. Test TEST TEST!!!!!!!
Test your map over and over again. Â Think it's perfect? Â IÂ guaranteeÂ its not. Â Someone will always find something else wrong with it. Â And don't get discouraged if people find a lot of glitches, just fix them so the next person doesn't have to experience them.
6. Watch some let's plays doing some adventure maps. Â What elements of that adventure map did you like? Â What didn't fit in too well. Â Get some ideas from other adventure maps. Â Don't just copy though, then no one will want to play it. Â Add some twists to the well known traps and puzzles.