I haven't even finished my game - but I already have learned A LOT! First time I'm doing a RPG and I had to face a lot of new things. Also the game itself now gave me the chance to place an easter egg in it. This wasn't planned! I just reached a place in my game from which I thought it wouldn't be reachable for the player. While I thought about how to prevent the player from going there I decided to allow it + reward him with an easter egg :-).
Now I hope that people will also find it once the game is finished + released ^^.