Well, I usually just start programming, as that's what I like, but always find myself adding stuff all the time. Usually stuff that don't fit into what I already have. That forces me to make hacks and take shortcuts to get it working again. It always end the same way, I rewrite it and when I am happy with it, I start the process all over again.
Not this time..... I think.
My design is going to be simple and I will stick to it. What I want is a playable prototype to build experience and get me to my goal. Try to make money of it and see if there is a market for simple home made games.
To keep this simple I will not be creating something real time with fancy animations thousands of npcs on screen and particle effects. It will be a simple version of a very simple game i played many years ago. Champions of Krynn. My game will only have the player controlling one character, he will be centered on the screen. When the player moves one square, npc's move one square. There will only be one class, warrior. Weapons and items should also be randomly generated and try to match the killed npc's level. So that if a high level player kills a low level monster it wont drop anything good, but the other way around, might drop something better than what the player already have.
Picture of Champions of Krynn
Major part of an rpg is gaining experience and skills, so will need to work that in somehow.
My maps will be random generated dungeons. I will not spend a lot of time creating maps. Random dungeons will also make it more fun for me to play as I don't know where everything is located. They will be generated based on something I haven't decided on yet, but if the player revisits a level, it should be the same, except all the monsters have returned.
If time and slick allows, I might add a few effects like light to make everything look better. It will not be a priority, but I will probably add hocks in my rendering loop to allow changing the alpha value of images based on lights.
Anything outside of this, should try to be avoided.