Not sure about the 'experienced' bit but from what I heard and read...
Cinder damage is excellent on all wis but someone said to add a bit of vita for the later game, perhaps that's what you could start doing at 20+.
One point to the colossus summon (also I added 1 point to the mastery there, for good measure, we'll see if that needs amending later)
Full points cinderwall and add to the mastery there, personally I'll just fill both
Lava...stream, is that the name? Adds fire resistance debuff and some minor AOE. I find I use it on boss only but unsure how much effect it has. It certainly looks great in theory.
Someone said to get Meteor with all the meteor extras maxxed for end game fun. Supposedly great range dd with area.
But...and there are two big buts. It's in the wrong skill tree. The description says nothing about damage being boosted by wis, only weapon.
I will certainly try it out but it sounds like yet another skill that was changed from other game versions.
What to look for in gear, no idea. I'm jogging around with 1 wand and one pistol at the moment, haha.
EDIT Pve only...in pvp people seem to use very different skills.