In order for you to get started on working on a rpg. You'll need to research "How to Create Characters?" to help you create characters, enemies, or whatever you want to use in combat. You'll need to get a "How to write a story?" book from the library to write the story for your game which would be useful. Get some papers and a pencil to come up with some ideas and write a story.
You need to come up with what fighting powers, and characteristics you want your characters to have. If you want to come up with a rpg with a party of monsters. Come up with moves and give them battle effects or abilities. For a party of characters, you may come up with skills or whatever and give them battle effects or abilities. For battle purposes, you'll need to come up with some stats for your characters. For example, HP, MP, and other stats.
You need to come up with what fighting powers, and characteristics you want your characters to have. If you want to come up with a rpg with a party of monsters. Come up with moves and give them battle effects or abilities. For a party of characters, you may come up with skills or whatever and give them battle effects or abilities. For battle purposes, you'll need to come up with some stats for your characters. For example, HP, MP, and other stats.