The basic questions are:
1.) What is your game about?**
2.) What do the characters do?**
3.) What do the players (including the GM if there is one) do?**
4.) How does your setting (or lack thereof) reinforce what your game is about?
5.) How does the Character Creation of your game reinforce what your game is about?
6.) What types of behaviors/styles of play does your game reward (and punish if necessary)?
7.) How are behaviors and styles of play rewarded or punished in your game?
8.) How are the responsibilities of narration and credibility divided in your game?
9.) What does your game do to command the players’ attention, engagement, and participation? (i.e. What does the game do to make them care?)
10.) What are the resolution mechanics of your game like?
11.) How do the resolution mechanics reinforce what your game is about?
12.) Do characters in your game advance? If so, how?
13.) How does the character advancement (or lack thereof) reinforce what your game is about?
14.) What sort of product or effect do you want your game to produce in or for the players?
15.) What areas of your game receive extra attention and color? Why?
16.) Which part of your game are you most excited about or interested in? Why?
17.) Where does your game take the players that other games can’t, don’t, or won’t?
18.) What are your publishing goals for your game?
19.) Who is your target audience?
**Denotes key question that should be answered/discussed first and foremost when designing a RPG.