That's right, you only get a percentage of fame for your club and online racing doesn't pay much out in the first place. Beating face-offs will help. There are also levels of challenge accessible through your profile and those pay out quite well. Otherwise, if it's just grinding you want to do, then pick a circuit and drift lots, beat face-offs and rack those point up.
Having other team members who are active is always best though, as once the team starts earning fame, it is rewarded with higher percentages of your own fame earnings as it progresses through it's own challenge list (manufacturer, locations, race type...etc.)
And there is also this thread:
https://www.gtplanet.net/forum/threads/grinding-for-fame.318259/