Things You Should Do When Making a Mod
Consider the mod you want to make. Are you going for a story-driven mod with diverging paths? Or maybe you want to focus on a certain era of human history? The first thing you should always consider before making a mod is what kind of mod you're going to make.
Know your limits. Try to refrain from having too many projects going at the same time. If you have 3 mods in the works and you're trying to focus your attention on one mod at a time, players who were looking forward to the other mods might be disappointed with having to wait longer.
Don't steal! Stealing content from another mod is one of the worst things you could do in development. You could get into some serious trouble with the developer of the mod you stole from, or with the players if they recognize whatever got stolen.
Fix the "September/August" bug. Go into the main localization files, look for the months of the year, and swap "August" and "September".
Correct the leaders' names. Kim Jong-un is misspelled Jom Jong-un in vanilla AoH2, and the first O in Moon Jae-in should not be uppercased. Also Winston Churchill is misspelled Winstion Churchill.
Fix the continents. In the vanilla AoH2 map, there are two provinces near the Caucasus that should be part of Europe, and two provinces in Madagascar that should be part of Africa.
Fix the regions. East China has three incorrect provinces. Crimea, Madagascar, and the Eastern Islands (Korea) each have two incorrect provinces. The region of Central Africa also has an incorrect province.
Do your research! If you're making a historical scenario, do some research on the year or era your scenario is set in. What was going on in each continent? Which nations existed? Which cities were capitals? Historical scenarios should be as accurate as possible to ensure high quality.
After completing a map, check the province settings. Did you set the growth rates up? How about the terrain types? The continents and regions? Details like that can make or break a map, no matter how many provinces it has.
DO NOT use the "Decision taken" trigger. This mistake killed my #1 mod and effectively puts every event-driven mod at risk of breaking. There is a bug in AoH2 where if you take a decision on an event and then save and reload your game, the game won't remember that you made that decision, thereby disabling any events that were supposed to trigger from the decision.
Don't use the "Have army" and "Have a core" triggers. Those are broken and will cause the event to always fire.
On the Forums
Bump your thread every once in a while. Players might not try your mod if they don't see the thread. Posting something in your mod thread will "bump" your mod to the first page of the mod list, where more people will see it.
Watch out for spam-bots! We all know those K-pop loving, thread burying spam-bots that keep flooding the forums with nonsense. If your mod gets buried by spam-bots and Łukasz isn't there to beat them with his shoe, you should wait until the spam-bots stop posting and then bump your thread.
Keep your players updated! Don't leave them in the dark for long periods of time! This may make the players think that your mod is stuck somewhere in development, or even dead! Every now and then, try giving them a little update on your mod's development. It doesn't have to be a big teaser. Even a simple "this mod is alive" will work.
Due to quite the backfire on a topic made months ago I will change the name doubt I'll be forgiven but one thing won't change about this topic is that we need to make sure that unoriginal modders are dealt with.