Give newbies some "free" defensive/passive skills which make them very hard to kill by other players in a PvP situation to combat ganking. Let them choose whether or not to later "trade in" these skills for others they might want. Doing so is not mandatory, but may be desirable. Of course, doing so will "open them up" so to speak to PvP combat permanently once they trade them in, giving them the choice to stay PvE for their entire career or go PvP once they realize it isn't.

Provide a "revenge" system in which victims of griefing (high level PvPer attacking a lowbie, etc.) can get a free bounty against that player, for other players to accept for monetary gain - which is then split 50/50 between the player who kills the ganker and the low level player who was ganked.

As much as I hate to punish players - punish gankers - NPC bounties, fines, higher merchant prices, "outlaw status" for x hours/days in which all NPCs will attack on site, etc. Many possiblities here

Of course, some of the most critical points to good PvP are to have goals and objectives, not just mindless player on player killing. Give them a good reason to engage in PvP - and make it as enticing as possible to encourage non-PvPers to give it a shot, and to also help them realize that it's not as bad as they once might have thought. This of course means we have to design systems that ensure it is in fact not all that bad. :)

[...] Psychochild started up a nice related entry to this with some great ideas posted by the community « Variance Shadow Mapping and Light Bleeding The Bandwidth Pit » [...]

I've seen something similar in a MUD, maybe Medieva? If your HP reached 0 you'd become unconcious and start losing blood. You'd only die when you got to -10 HP. If somebody could stop the heavy bleeding you'd be alright, otherwise you'd bleed out.

- Have an alignment/class system like Ogre Battle (really old SNES RTS).

- Players can change class at any time (perhaps by spending money).
- The advanced (hence more powerful) classes have alignment requirements: Good (e.g. pally), Neutral (e.g. druid), Evil (e.g. necro).

- If you attack or kill a much lower-level player, your alignment goes down. Once your alignment drops below e.g. 70%, you become "neutral". Once your alignment drops below 30%, you become "evil".
- You can raise your alignment through showing mercy (refusing to kill a defeated enemy) or helping the weak (rescuing a newbie from a ganker).
- If you can no longer fulfill your class's alignment requirements, your character reverts to a basic class with no alignment requirements.
- One possibility: Players don't die when their HP reaches 0. They enter a state where an opponent must use a special "execution move" to finish them. If they are not executed within a certain timespan (10 seconds??) then they have some kind of escape option (perhaps being able to teleport to a safe zone, or being invulnerable for a short while but unable to fight).
- Another possibility: Players might have abilities which allow them to knock a weakened opponent out, rendering him invincible (to prevent them from helping an evil player to gank him) but unable to act, and effectively ending the fight.

I'm sure there are ways to game the system, but it seems to me that this would introduce an interesting dynamic if managed right. Many players like to think they're good people (see: Alliance zerg in WoW), so why not lean on them to "earn" their goodness? Picture the newbie dropped into a raging battlefield: within seconds, an evil necromancer swoops down on him, unleashing a bolt of dark energy. His HP drops to near-zero instantly, and he's about to collapse. The necromancer raises his bone scythe to deliver the finishing blow, but before it lands, an armored paladin steps in between them and the scythe clashes harmlessly off his tower shield... Of course, the paladin is merely farming alignment, but our newbie doesn't have to know this ;)

1. Give folks something meaningful to fight over. Many PvPers will get into ladder scoring and such, but if you're going to set PvP in a VW, then you might as well give them some kind of additional hook - something that encourages them to keep fighting even when they're not on the winning side. This is especially important if mass PvP is the goal - you need to have some kind of RvR-style objectives.

2. Rock-Paper-Scissors balance. So many games get bogged down in "he said, she said" between classes or skill sets, and generally all this accomplishes is that it homogenizes people's characters, or leads to flavor-of-the-month skillsets. It's better off if you design from the beginning with a rock-paper-scissors balance - so you know up front that as designed, a rogue should be able to beat a priest, but a warrior can defeat the rogue, but a wizard can defeat the warrior, but a priest can defeat a wizard.

3. Minimize the impact of gear, and avoid large incremental increases in character power. Sure you want to have some - everyone wants to see their characters advance - but ideally you want a system where the skillful newbie can bring down the lazy veteran in a fight.

4. Include social hangouts. Just because most of your gameplay is built on gladiatorial combat doesn't mean that gladiators don't have lives outside of the arena. Give players places to meet, swap stories, and make friends, and reasons to do so (this is easy if you have a PvE game as well).

5. Avoid complicated rulesets. If you need to throw a bunch of artificial restrictions into your PvP system in order to insure fairness, then you need to redesign the system. Complicated rulesets just encourage players to find loopholes and discourage players who want more "free-form" action.

Those are my thoughts for now..

http://brokentoys.org/2007/12/10/how-to-make-a-game-with-pvp-done-right/

If attack first and kill a player with a lower level, you lose all abilities and stats above that level for 24 hours. If you kill a player with a higher level you gain those abilities for 24 hours. Losing doesn't affect your status. Of course we're now into the territory where it's worth a low-level character provoking a high level character into attacking them just to grief them, but that hopefully would relatively rare and could be handled by normal abuse channels.

Assuming there is some other reason for taking the combat risk - factional points, gold, kudos, ranking.. there should still be enough incentive for combat, with a real (but only short-term) risk.

A skilled player could bring in a Level 1 char and be running at Level 80 pretty quickly - if they have the skill, but they have to keep killing (Players of a comparable level). Could be a interesting (or insane) mechanic in a vampiric setting. Not a great way of reducing obsessive play however. (Perhaps it should be 8 hours of 'online' time)