The Map Maker's Checklist
First of all, why are you writing a map? Get this clear in your head and it will help. No use to write it for yourself, by the time you have finished with it, you will be sick of the sight of it. I wrote mine because I felt there weren't enough maps for the average player. Most maps are written for the expert player. I'm not an expert player, and there are a lot of us out there.
What is the category of the map? They fall into 2 general categories: story & strategy. However, any good map contains some of each. A strategy map gets quickly boring if there is no story. For the best example I know of a great combination of both see Time of Testing by Cattleman & The Fiery Phoenix.
Higher level notes on story construction: do you know what your style is going to be? Some approaches are Historical, Humor, Grim Humor, Pathos, Self-discovery, and Irony. Keep the story going. It isn't enough to give a low down at the beginning. You should have some new information for the player at least every two weeks, preferably more often. This doesn't have to be critical information. You will, in most cases, need to impart that within the first week or two. It can be insights as to what heroes are feeling, or their background, or history of how the situation the map is based on came to be. Rumors are always fun, but don't rely on them to impart necessary information. You can not control what the Tavern says each week. (At least not that I know about. If I'm wrong about this please let me know.) The game may be ending when the Tavern decides to display information that would have helped at the beginning. One thing you can put into rumors that is often overlooked is how the town people view what is going on.
Who is your audience? Who are you writing for? Do you want it to be a challenge for the very best players, or do you want it to be one most players will be able to enjoy and finish? I'll bet you never dreamed how much head work was involved in this.
How large does this map really need to be? Too many maps are overly large and waste player's time. Remember most people do have other things they do with their lives. (Well, some do, don't they?)
Decorate, decorate, decorate. Large grass spaces are useless in most cases and boring! Tips on decorating: layer-several layers are often needed to achieve the look you want. Guys, don't be afraid of flowers, they are not gender issues. Even though the Editor separates landscapes into nice neat categories, it doesn't mean you have to do so. Mix those types! Now for the next steps, you will just have to figure out for yourself.
Ok, so now you think your map is finished? NOT! First validate in the editor to make sure you haven't accidentally blocked something, or mismatched your portals. Next export your text and open with a text editor. Check your spelling and grammar. No need to look stupid if you can avoid it. If English is not your primary language, that is another story, but you still need to edit it. However, you must be careful not to insert anything other than spelling changes/grammar corrections. This includes not creating any new carriage returns, otherwise you won't be able to import the corrected version. Now save, as text only file, and re-open map, then import and save map. While you have the text in the editor where you can see it all, check it for consistency and accuracy.
You've only just begun. Now you play the map, and play the map, and play the map, until you can't stand to play it anymore. Go everywhere on the map. Things that don't show up as blocked can still be inaccessible. Play all sides, even those which would normally be AI. Next, cheat. Use the cheat code to display the map and watch closely all the moves each side makes. They may not be behaving as you would predict they would. Don't trust AI, if threatened with defeat it will cheat like mad! It will also do other strange and unpredictable things you never dreamed of, and probably 3DO didn't either.
Another thing you are watching for while you test is balance. If all sides are to be of equal strength, are they really? Does the action hold up at the beginning, mid-game, and end? Some maps have very slow starts, which can lead to boredom and frustration. Some maps have good mid-game, but then, ho hum. This doesn't mean your major battles can't be before the end though. Some times you will want to fight the good fight then get the easy reward. The Faerie Dragon Scenario is a good example of this. The end, if you know the trick is truly easy, while getting there is a b*. Just make sure the story and action doesn't lag. One way to make sure the action doesn't lag at the end is to not draw it out with long travel that accomplishes nothing.
Next, if you can whine, bribe or otherwise get your friends to test the map, do so. Ask them to be honest and be prepared for negative feedback, just in case. Don't lose a friend over it. Now, finally, if you so desire, your map is ready to submit to places like Celestial Heavens, and H3Trio. Well, I know there is more that need to be said, but I'm worn out and simply can't remember anymore at the moment. If you remember all this, you will be exceptional anyway.