Templar healing build focused on large heal ticks and HoTs with a good deal of resource recovery. (current set-up is for stamina DPS. You need to adjust your moves depending on your DPS)

GEAR:
Engine Guardian/Skoria. If you need extra sustain, EG, if you need extra DPS, VS. (preference)
5pc Spell Power Cure is recommended, but something for sustain (if you need it) is fine. Things like Warlock, Lich, etc. work here. I've healed just fine in Julianos though, so if you don't have the means to get those...
3pc Willpower (arcane is ideal, but a few healthy won't hurt that much)
DSA Resto staff with powered, or any resto will work- just use powered/precise.
If you have it, a MSA Fire Staff with precise/sharpened, but you can get by with any staff
Note: I like having divines on the small pieces (shoulder/arm/belt/shoes) and infused on the big pieces (head/chest/ legs), but player preference is king.

MOVES and EXPLANATIONS:
Resto---
Healing Springs- Refunds some magicka per ally hit and a very easily spammable heal (I hit (average) 5k per crit tick)
Ritual of Retribution- nice Dot and Hot that cleanses, keep this up on the tank 24/7 and walk back to your Channeled Focus
Breath of Life- Beastly burst heal, don't just spam it. You'll run out of magicka; Hots>Bursts. Use if needed...
Siphon Spirit- keep up on bosses/beefy enemies, don't just cast on trash as it has a long cast time- sustain
Inner Light- I like 7% more magicka and some crit, the 2% regen doesn't hurt either
ULT: Reviving Barrier- You could use Rememberance if you want, I just like the recovery boost and the breather

Destro---
Blazing Spear- throw to tank/melee DPS. If it disappears, chuck another one- they won't complain... Adds some DPS
Channeled Focus- gives 25% healing buff, armor and some magicka regen. Keep it up if possible for sustain
Repetence- Easy access stamina recover/burst heal- can proc off of dead sphere to help with bosses if you use EG
Radiant Glory- I chose this morph as the healing has made sure I don't die during execute quite a few times
Inner Light- *see above
ULT: Aggressive Horn- 30% crit damage is nothing to scoff at, plus it raises stat pools by 10%. Use as much as needed

Notable Mentions---
Elemental Drain- helps the magicka DD (based off of elemental damage done). As most magicka DPS use (or should use) Wall of Elements, this works nicely with that. Plus, it's the main reason (besides weaving) we use a destro
Mystic Orb- really useful in large-scale PvE/PvP. Costs a good deal, but helps out the magicka users a lot
Combat Prayer- decent burst heal, while giving a nice damage boost. If you have space, put it in
Purifying Light- I don't bother with it personally, but it can offer some nice healing focused on a boss/enemy and provide a modest damage burst. If you use it, make sure to keep it up
Puncturing Sweep- I use this on occasion, mainly when we need more DPS, but if you do solo content, this is a must
Wall of Elements- same as Sweep, just add this in while sweeping/weaving. You can use this if you want to reap the benefits of Ele. Drain. I use when magic DD/large add pulls, as it can give me magicka per kill
ULT: Nova- some damage reduction/DPS. It can work on stationary bosses/adds, but I find it kind of redudant
ULT: Remembrance: I like this morph more than the other one as it gives a nice damage reduction. I feel it under- performs compared to Reviving Barrier as it makes you unable to heal for the duration, but it is 75 ult cheaper.
ULT: Meteor- Once again, while it does more damage than Nova, I still feel it under-performs compared to Horn, but it's your preference

CONCLUSION:
This is how I heal personally (crits and HoTs), so your experience may change with this build. A key point in healing is knowing the mechanics (don't be afraid to tell somebody to move from the red or boss mechanics). You are the second line of defense, and because of this your job is to not only heal, but give resources and damage buffs (the tank should be helping the damage buffs/CC too). Of course every healer has a way they like to do things, so don't be afraid to tweak some things, or use non PvP ults if you need to. I healed in Julianos for the longest time because I didn't like farming WGT, so that's an option. If you have any questions, feel free to comment and I hope this build helped you become a better healer- as everyone is still learning. Don't be afraid to add some DPS, just tell the group what key moves you'll be swapping as this could change the way they play.

Remember: healing is dynamic. You can't sit back and wait for the adds/boss to die, you need to contribute some damage. Of course, your top priority is keeping the group alive and keeping their resources high.