How do you best optimize playing with the PS4 controller?

[Niwashi]

Up/Down - target party members, cycling in the order they appear in the party list
L1 + Up/Down - target already aggroed mobs, in the order they appear in the enemy list
Left/Right - target according to your current targeting filter, but in a seemingly random order

You can adjust your targeting filter a couple different ways. As ChameleonMS mentioned, you can set one filter for when your weapon is drawn and another for when it's sheathed. Or another option is to set a few different filters that you can alternate between using L1 + (triangle, square, circle, or X). (You don't want to have both methods enabled, though, or they'll interfere with each other.)

it says max 1000 chars which is next to impossible

The workaround to that is to post part of your message, and then edit it to add in the rest. For some reason, the forum only checks that "1000 chars" rule when initially posting a new message, but not when editing it.