At the start keep the necklace and use those as your main magic skills. Later you should get Cinderwall as your main attack and kite monsters to it. Then you can reset and get the Lava Field+Meteors passive. Later on, you should be able to reset and get the Wisps tree instead. Max the Wisp tree, especially the last passive.
For attributes, you'll mainly use Wis equips, so add the most points to it. Then you should add to HP too, as bosses on levels 45+ get horribly strong and may be able to OHKO (one-hit-knock-out) you.
1. At the start, use newbie equipment (necklace) skills. Add points to Coalsmasher tier (plus sign on upper right section of skill tree)
2. By level 5, you should be able to get Cinderwall. Max it and use it as your main attack skill.
3. By about level 10+, you can reset and get the Lava Field (slow+add weakness to fire) and its Hail of Magma passive (adds damaging meteors).
4. By level 15+, put one point on Wisp, then max out the passives Gathering Lights and Ember Torrents. At this time, you can basically just run around and the Wisps will destroy everything.
*After that, just max the Wisps, then put some points on the Burning Colossus (tank summon). Add some points on to Lava Field+Hail of Magma too, since the weakness to fire is amazing. Once those skills are done, you're basically free to add anywhere. Remember to grab Minion-stat equipment later on.