Agreed, level across the axle first, remember if using a ramp reverse the caravan up it, this way the brake will hold it there, if you drive up the wheel will turn 1/2 a turn back before it locks! I'm going to use a plank under the oposite side to the ramp to stop the wheel that side sinking in.
when leveling 'front to back' use the jockey wheel to adjust the angle DO NOT try to lift it on the corner stedies. if you are on an extreme slope you can rest the van on the front stedies whilst you drop the jockey wheel more to get more lift out of it.
Then I go for the power next, if you have slaves, sorry, kids you can send them off to get water whilst you level up!!
One last thing, if in doubt, check the power cable will reach your chosen spot before you level etc!!