Healer is really a misnomer you should really be called support, you can heal, you can boost DPS, you can help with resource management, and you can DPS. Your priority is probably as listed although resource management might be more important than increasing DPS at times. The point however is if you are taking care of priority 1, 2, &3 you can DPS.

Think of a healer's priorities as follows:

Top Priority: keeping the party alive with heals/shields

Second Priority: buffing the party (I include providing resources through shards/orbs in this category as you're buffing their sustain)

Third Priority: directly contributing to the party's DPS

You need to plan your setup based on those priorities, and where possible use skills that contribute to more than one of those priorities. You'll want a few skills that are purely focused on your top priority (you need at least one HoT and at least one burst heal), and the rest of your skills should mostly be selected based on contributing to more than one of those priorities. For a few specific examples:

Combat Prayer helps with both your top priority and your second priority, and is therefore very useful - it's up to you to make sure that your positioning is such that you can catch the rest of the group in it (you won't always be able to get everyone in it, but you should always be trying to get your positioning such that you can maximize the number of people in it). If your positioning is good, I consider it to be a more effective group burst heal than Breath of Life (since it changed to only affect 2 targets), and on top of that it provides buffs.

Shards (either morph, although I prefer Luminous Shards to be able to use this to help people with their magicka) helps with both your second priority and your third priority, and is therefore very useful to use at times when everyone's health is high/full.

Orbs either helps with both your top priority and your second priority, or with your second priority and your third priority depending on which morph you take. I personally prefer the Mystic Orb morph, because I usually have more than enough heals on my bars and don't need any additional help with the top priority, so I'd rather use this skill to contribute to group sustain and DPS than heal and sustain.

Once you feel like you've got enough skills fully focused on your top priority, and enough skills that help with 2 of your 3 priorities, you can fill out the rest of your bars with whatever you feel will make your groups more effective. For me I usually like to finish my bars off with a couple of pure DPS skills, as I usually find that by providing a decent amount of DPS in between heals and buffs, I can help make the fights shorter, which makes it easier to keep everyone alive through the fight.

Only ever use a pure DPS skill at times when nobody needs healing, and you've recently applied buffs, though. The rest of the time, if you're going to use a skill that contributes to DPS, make sure it's a skill like Shards or Orbs that also contributes to healing or buffing the party. Radiant Oppression is a tempting DPS skill for a Templar healer to slot on one bar (that execute can be fantastic, and really massively help a fight end more quickly), but it's also a potentially dangerous skill for a healer to be using, as it's a channel and if people in the party get hit with burst damage while you're in the middle of channeling it, you may not be able to burst heal them quickly enough to keep them alive. If you slot it, only use it when you're sure it's safe to do so. If your finger slips and you accidentally use the skill at a time when you didn't intend to, bash to interrupt the skill and get back to what you were doing immediately.

That's my advice anyway.

Oh, and even in PUGs you should never need to be healing the entire time. In every fight there should always be times when you're using skills to buff and/or provide DPS without worrying about healing. I've been running a ton of PUGs over the last week as a healer (my only VR character on my second account is a Templar healer, and I've done a minimum of 2 PUGs with him every day since cake arrived), and with good PUGs and bad, never once have I had a fight where I needed to be healing the entire time.

Yes! Only heal you really need is rapid regen throw on some combat prayer for more deeps Bol for ppl that can't get out of the red and repentance for trash mobs