-Load up in a zone you don't plan on farming in, then travel to the area of your choice
-Always play defensively = check map, shoot first then relocate, etc - (Do not assume people are friendly at first, assume the opposite)
BIGGEST TIP = Get the ability 'never without one' - it requires you to be level 48 (I know) but this gives you a free headshot to retaliate before it is too late, if you are on your horse you can quickly equip another hat
-If you are a fisher, use the companion app to bring up your map to see if you are being rushed.
-BUY horse insurance.
-Avoid major hotspots when farming ( blackwater, saint denis, valentine = depending on the population of server)
-Ride to a farther butcher if needed, just hunt along the way.
I personally have never been griefed, but these little tips have helped me out. I also shoot everyone that rides directly at me first - but I don't pursue them afterwards. Think about it, even the npcs get angry if you ride to close....
Good luck out there - hope any of these small tips helped.