Slot Rapid Regen and spam it on allies in fight.A few tricks I've developed over the past year if you're going for an Emp run:
Save up every cyrodiil quest turnin for until after the campaign resets (once scoring starts) to turn in.
Get the +20% Cyrodiil cave boss buff with regularity by being aware of nearby caves. Make sure you have this for the quest turnin at the begining.
Don't focus shield stackers if given a choice. Instead focus players that you can do damage to their health on as damage done to damage shields reward you with zero AP. The AP share that you receive is directly proportional to the damage you did to their health.
Don't bother attacking players you've just killed as they give no AP. Try to focus players you know haven't been killed recently. Nightblade stealth gankers are almost always worth full AP credit if you can catch them and kill them.
Only group if the group is as high of quality as you are and are not competing with you for Emp.
Scroll defenses, even unsuccessful defenses will always give you a defensive AP tick. Bonus points if you can find a couple of enemy players and utilize stall tactics to kill them slowly and extend the tick while waiting for the rest of the defenders to chase the scroll out of gate zone. I've done that once to the order of a 25K Tick.
Some less Savory Tactics employed by some:
Whenever there is a large successful defense, try to misdirect players by yelling something like "Large AD force Incoming to farm" to get players to run out of the defensive area and increase your tick. I've seen that work with varying levels of success.