Openers
Highest Damage: Shield Lob(Spirits Within*) -> Fast Blade -> Riot Blade(Fight or Flight) -> Goring Blade(Circle of Scorn) -> Royal Authority Combo -> Royal Authority Combo -> Goring Blade Combo -> FoF ends.
*The timing of this use depends on how close to the enemy you are when you lob. If you can fit it in without delaying Fast Blade, go ahead. Otherwise, use it after Fast Blade.
If you're tanking something, at least one of those Authority combos should be Halone. After the first Goring Blade, just use the off GCDs on cooldown, with Shield Swipe being a priority most of the time because it can only be used for a limited time when it procs. If you want to maximize enmity(threat) instead of damage, replace as many combos as you deem necessary with Halone, but do try to keep Goring Blade up if you can. It is your most powerful weaponskill and therefore helps with both DPS and enmity.
Fighting high initial burst from DPS: It is generally considered to be a poor use of Fight or Flight to apply it just before the initial Shield Lob. However, if your DPS are bursting hard enough that you cannot establish enmity quickly enough otherwise, it may be necessary to do so if you don't have anything else to help out(ie. a Ninja, more gear, etc.).
Basic in-battle rotations
What you're doing in battle depends on the current situation. Are you Tanking right now? If so, how much of an enmity lead do you have? Would Halone's Strength Down debuff be useful for survival?
If Halone is Necessary(for enmity or Debuff): Goring Combo -> Authority Combo -> Halone Combo -> Repeat
If Halone isn't Necessary(High enmity lead or Off-tanking): Goring Combo -> Authority Combo -> Authority Combo -> Repeat
If you're really behind on threat: Goring Combo -> Halone Combo -> Halone Combo -> Repeat
Don't be afraid to apply Halone while off-tanking if it would truly be helpful. However, it will not frequently make that difference. With time you'll learn how to make that call.
Tips
- As Sapphida posited above, do try to save Fight or Flight for use right after the second hit of a combo. If you really can, try to save it for just before a use of Goring Blade. However, don't leave it off of its cooldown for very long; you want to use it as much as possible no matter what.
- Never ignore Shield Swipe. It's off the global cooldown - which means free damage! - and it carries an enmity multiplier. Paladin already gets the short end of the stick in enmity generation, so anything will help.
- Unless you need Sheltron for a specific attack, pop it whenever both it and Shield Swipe are off cooldown to get that extra attack in.
- Further regarding Sheltron use, it is as instant as a Paladin's other cooldowns. If the attack you're watching for has a cast bar, wait until you see the bar to activate Sheltron. This way, you'll block that specific attack and not the autoattack right before it.
- When Flashing a group of mobs, try to stagger your Flash use to let the Blind last as long as possible. This is, however, rendered void if your healer is a White Mage casting Holy at the beginning of the pull, as the mobs will be stunned during most of the duration of Blind.
- Convalescence is a friend. If you have a healer that is providing consistent regens to you(White Mage or Diurnal Astrologian), try to time its duration to fall during the time that regen would be reapplied.
Advice
- Don't ignore your Utility! It may seem situational or maybe even downright useless at times, but keep those abilities on your bar. Opportunities to gain mileage from them pop up more often than one might think; you just have to keep your eye out. Ignoring them entirely is ignoring what makes a Paladin a Paladin and will result in a much more boring gameplay experience.
- Use Cooldowns on Trash. In fact, you should use them very often in all situations unless there is something in an encounter that you are specifically saving them for(ie. A Tank Buster). Even then, keep an eye on times. If you find openings to use your cooldowns while still having them ready when they're truly necessary, use them!
- Don't get too down if a fight is solely throwing Magic Damage at you. Fights with this configuration are a minority in the game.
EDIT: Adding a specific Spirits Within timing to the initial few hits.