Tanking Troubles - HELP!

[JimboTCB]

Well if you just hit 40 you should have Shield Oath now, which will help massively. The number 1 mistake I see lowbie paladins making is not flashing enough. Before you get ShO it really doesn't do much at all, you need to spam the crap out of it, but I constantly see tanks facepulling mobs, flashing once, and they just single-targetting one of them. Healer peels mobs off, over-eager DPS start AOEing and peeling everything except the tank's main target, everything goes downhill.

At your level, against 3+ mobs you should be spamming the crap out of Flash. Even on pulls with just two mobs, flashing three or four times at the start of a pull will generate enough holding aggro to keep aggro on both mobs while you focus on one. Later on when your gear is better, you can get away with flashing less and just manually cycling through enemies using your single-target rotation, but at least until 50 Flash is your only tool for generating threat on multiple targets at once, and you should be using it almost constantly.

[cgbspender]

Mark the enemies, #1 #2. I usually just use #1 myself and switch the marker to another enemy when the one being killed is around ~10%hp. That should give enough time to the dps to prepare switching to the next one and not shoot blindly.
Even though you are supposed to be using your enmity combo on every mob and flash regularly, marking mobs is - IMO - very important at first. Both for you and the others. It will make the kills faster and will be less hard on everyone. This way, even if you forget to combo one enemy, it will be less punishing if the players are hitting the same enemy all at once.
If by mistake, one of the enemy gets away from your flashing, it will be easier to get it back, as players won't have stacked a big enmity if they have been focusing on the marked one before.