I should have asked in my last post, but any tips for a burgeoning tank? I'm still sorting out a decent opener for grabbing groups of mobs (going tomahawk > overpower > flash for now, but will exclude overpower when certain mobs need to be slept). Also gotta sort out my hotbars better, as I'm noticing I need more of my abilities at the ready at all times compared to other classes I've tried.
It sounds like you have the basics down. There are two big risks when tanking: losing aggro to the DPS, and losing aggro the healer.
You can lose aggro to the DPS if they are either attacking targets you are not, or you are not producing enough aggro on the main target of attack. The latter is very rare unless you are not using your main aggro-producing combo. The former is mostly fixed by either marking the targets, or adjusting your main target of attack to what the DPS are focusing on. The good news is that for the most part, DPS will generally struggle to produce anywhere near as much aggro as you unless they are much better geared than you.
The main reason you might lose aggro to the healer is if you are not keeping up aggro gain on the enemies that are not the main subject of attack. The best way to deal with this is mostly just periodic uses of Flash or Overpower. Using a couple flashes or hits of Overpower at the start of a fight, followed by one every four or five hits or so is generally sufficient. You need to make some adjustments based on how much healing is being done and whether or not your party is going nuts with AoEs, though.
The most critical step when tanking is the opening pull, though. Your first priority is to establish aggro on all engaged enemies. If their name is still orange, than the first healing spell cast will pull them straight off you and onto the healer. Pulling with a tomahawk is a good move, but make sure to hit
all of the enemies with a follow-up Flash or Overpower.
Other than that, my only suggestion is to not be afraid of using your defensive cool-downs. They recover fast enough that you can use them fairly regularly, so don't feel like you need to save them. If you feel like you are beginning to take an unsafe amount of damage, use a cooldown such as Foresight immediately.