When attempting to dominate planets, take a full force of escorts along with you. Preferably, each of your escorts will be equipped with fighters. My planet-dominating fleet varied (as a result of casualties) during the Crescent campaign, but typically comprised two Azdgari warships, three Zidaras and a Crescent Warship (ex bounty hunter).
Don't feel ashamed at letting your escorts do most of the fighting for you. They aren't being shot at - you are! Charging into the fray, even in an Igazra, will you will eventually run out of shields, and the business of EV warfare becomes really dull when you have to play on the defensive while 500 points of shields are recharged. Besides which, if you fly near your escorts, they might get hit by gunfire aimed at you.
Your approach should be to demand tribute while a long way from the planet. A defense fleet may launch up to six vessels (I think that's the maximum), and then launch new ones to replace any losses incurred. Launched in this way, enemy ships will become strung out in a long line. Make sure you remain on more-or-less the same bearing from the planet! This forces every defense fleet ship to run the gauntlet of your escorts. By the time they reach you, a burst of phase fire should finish most anything.
If you're using a 'Python tactic, remember to fly back towards the planet (keeping on the same bearing) during quiet times. Otherwise, you might find yourself bouncing off the edge of the system in mid-combat, which is disorienting and can lead you to suffer damage.
One final word - make sure your ship is equipped with weapons which the defense fleet use. Against some planets' fleets you can run out of guided weapons very easily. Plundering your foes will help to keep you in fighting shape.
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