What engine are you using?
First of all i recommend you:
- To start something small,
- Write down main plot and ideas
- Think in the gameplay and if you will add some engines
- Look for non RTP resources (or make them)
- Keep on working on the game
- Finish it and publish.
After all this has been done just tell me what kind of help you need and i'll gladly help. In fact it's a good chance to start making video tutorials.