Facebook - Under the Radar

Hi guys,

I was wondering is there up to date list of rules that should be followed so Facebook don't mark your account as suspicious?

For example, I was temporally blocked two times in two day:
When I send request to join +15 fb groups in short amount of time (approx 5 min)
When I invite friends to like my fb page with option something like "send invitation to messenger too".
(Before that I send +50 invitations without any problems, without that option).

Also, I'm wondering is there some limitation regarding number of "friend request" that I can send in one hour or?

you might have used your account only for seo activities so facebook might have marked it as spam. delete the account and create a new one and maintain that account like a general user