Well in general a good crossbar setup has all your often used abilities on main bar, and cooldowns on other bars, with a normal line bar somewhere on the screen with the cooldowns so you can see when stuff is up at all times.
For a paladin, I'd do Halone chain+Spirits Within on front buttons and Shield Lob, Provoke, Fight or Flight and Riot Blade on Dpad for R1(or well R2 is default but I prefer R1), then Flash+Circle of Scorn and Shield Bash and Shield Swipe on the other front. Then I'd put all the cooldowns on whatever you're comfortable with on the Dpad left and the secondary bars and that's pretty much it. Paladin is very simple overall because it has so few active skills and so many cooldowns. After that it's just a matter of remembering where the cooldowns are, but you put like the common ones(Rampart Sentinel Convalescence Foresight) together on L1(L2) Dpad, then the less common on the other tabs(Hallowed Ground, Bulwark, Tempered Will, Bloodbath). Then that leaves a few buttons to put like the 2 oaths and Awareness and Cover. Maybe Stoneskin too somewhere. This should more than easily fit on the 2 enhanced bars, in fact if you combine the 2 oaths in one macro(which I think works, I know on my ninja I have both Venoms as a macro and pressing it just swaps to the other one), actually fit on a single one if I'm not mistaken, leaving the 2nd one for shit like mount, potion, recall, TP, marks and whatever else you want.
Also for selecting targets, a friend mentionned that you can press a button then use up/down on the D pad to scroll through the enemy list that pops when you're in combat. Great for picking up adds and shit, or for selecting a particular enemy in a sea of enemies based on their threat(the one that's not red isn't on you, so you just scroll down to it and hit provoke+shield lob or provoke+halone if in range). I wanna say it's L1(the actual L1, not my rebound L1) but you might want to check around, just pull 2 random lvl 1 mobs and see which works.
