HDL

I've started other threads on Paladins, but we're getting down to basics with this post.

Right off the bat, you should be specc'd for Protection. You can't tank a raid in Protection gear and Retrbution specc'd. Your talent tree should follow the classic build.

Ensure you have some solid macros before headed into the raid. Some of them are not as essential with changes to spells (Righteous Defense being an example), but I still have it macro'd since it makes me happy.

Taunt:

#showtooltip
/cast [help,nodead] Righteous Defense, [target=targettarget,nodead] Righteous Defense;

I usually have one or two macros that set my current target as focus, target a player (healer), cast Blessing of Protection, and then refocus. I almost always rewrite this on the fly so my healers' names are used. This mitigates the chance that your BoP yourself, the OT, or DPS. Alternatively, /focus your desired healer, and then cast, as so:

/focus Squishiehealer
/cast [target=focus] Blessing of Protection

Consecration is a mana drain. This will keep consecrate ticking for enough to keep threat going, but not drain your mana. Right click to start and when you need a little more zing (when a mob peels off), and left click to keep threat going.

#showtooltip Consecration
/cast [button2] Consecration(Rank 1); Consecration

Spell rotation in your engagement of the enemy is critical. On trash, the rotation should be:

Activate Seal of Righteousness
Activate Holy Shield
Cast Avenger's Shield if needed to pull
Engage
Drop Consecrate full rank
Judge Righteousness
Reapply Holy Shield

Repeat the steps that bear repeating - keep Consecrate up, keep judging Righteousness, and ensure you have Holy Shield up at all times. If you have time or need the boost to Threat, start with Seal of Crusader, and Judge that, and follow with Seal of Righteousness.  You may need to apply Wisdom if your gear means you're not taking enough damage to get enough heals to make Spritiual Attunement tick health.

Avenging Wrath should be used as necessary to build even more threat. I don't use it that often as I want to ensure the cooldown is ready for Blessing of Protection. As we raid more often and people are more comfortable with their class, I'll use it more.

I hope this helps!