This is probably the place to start.

Magic of any variety has many different possible outcomes. You are not likely to get what you want until

1. You understand what you want
2. You understand why you want it
3. You have studied many different paths to attain
4. You have used magic to propell yourself to attain other achievements, successfully.

Before jumping headfirst into demon work, consider preparing yourself by working with servitors. Meditations and ritual designed for invocation and banishing will also help you prepare and strengthen your mind and awareness of self.

Demonology is one path. Set out on your journey, what ever it is, having brought tools.

All the best.