Griefing in Minecraft is very fun because ive had it on countless servers so a lot of players hate each other and some players really do hate each other. So griefers will generally only attack other griefers. You can avoid griefing by using a server wide voice filter, this will only mess things up.
The best time for a griefing session is at night time, because the people who are actually killing you will have to deal with you. You will need to get a lot of mobs out of the ground like redstone traps etc. You will need to use a lot of griefing to kill an enemy that is in close combat with you, the more grief you use the more time you have for the battle.
Griefing in Minecraft requires a lot of teamwork because you will need to manage your mob spawn and the mobs that you want to attack. You need to manage your mobs and your surroundings to be able to defend against the mob attackers.