I have a lvl 32 priest that I started a week ago, and I'm working on a smite build.
Below are some must haves in my opinion:
1. Spirit Tap (Shadow tree) - this is an awesome leveling talent that really helps with downtime. The only time I med is when I'm taking on mobs two levels higher than me (I don't usually do this) or when I'm taking on three mobs.
2. Wand Specialization (Disc tree) - Get the best wand you can find for your level. Here are a few I recommend:
- Lesser Magic Wand - level 5 to 12
- Greater Magic Wand - level 13 to 18+
- Gravestone Scepter - level 18+ - this is a reward from the Blackfathom Villainy quest, and you can get it as early as level 18 with a friend running you through BFD or in your low 20s if you find a group.
- Dancing Flame - level 25+ - this is a reward from the Final Passage quest. It is a lengthy quest chain starting in Thousand needles, and it would require help at level 25 since it involves Scarlet Monastery.
3. Holy Specialization (Holy tree) - You'll want the extra crit for your smites.
4. Divine Fury (Holy tree) - Reduces cast time on Smite and is a pre-req for Searing Light.
5. Searing Light (Holy tree) - Increases Damage for Smite and Holy Fire
I'm working to finish Divine Fury so I can then move to Searing Light. I'm not sure where I'll go after that, but I think that is a good start to a Smite build.