If you have a radio ID associated with the TG it will be much easier to begin guessing. It's actually easy to figure out at least what area the radio is from. The guessing begins to get a little tougher to narrow it down and takes more monitoring but can be fun and very rewarding once you determine who it is. Then you can submit the details to RR and share who the TG belongs to.
Good Luck
Les
Look here for details of how to read the radio ID's