I think there are entire library shelves dedicated just to this issue. If you want actually useful information, you should probably specify what kind of graphitic material you want (crystal, flakes,...) or what you want to use it for (semiconductor applications, lubricant...).

Just graphitizing carbon doesn't necessarily generate something useful.

I think there are entire library shelves dedicated just to this issue. If you want actually useful information, you should probably specify what kind of graphitic material you want (crystal, flakes,...) or what you want to use it for (semiconductor applications, lubricant...).

Just graphitizing carbon doesn't necessarily generate something useful.

There are (at least) 100 years of carbon science published on this exact topic.

Graphitization is most strongly dependent on temperature, then pressure and time.

You can try using Google and search "carbon graphitization" or start with the classical papers by Rosalind Franklin.