First off, add a raidable castle, this is a guide to make a good castle:
How to Make the Front of a Castle
Next, always add quests, here are a few exaples: Slay a dragon, raid the castle, and slay 10 - 20 sentries. Use this guide too:
Quest Guide Part 1
Another thing, add fun side things, like a ray cannon:
How to make a working Railgun/beam gun
Maybe also add achievements too!
How to make an Achievement System in Gimkit
Here are some more guides to look at:
How to Make a Medieval Marketplace!
How to Make a Medieval Basketball Court
How to create a forge! (mini guide) 0/10
How to make your houses in an RPG or story map look better. Diff: 2/10 or
Hope all those guides helped!
Extra stuff
I know there is a lot of guide links, but because there’s a guide on these, I don’t want to re-make them.