[2.2 Perandus Question] Build questions and improvements

Hi all, i'm currently trying a fire nova mine build and I would have a couple of questions as to what I could improve in my build and what gear would be optimal for me. Here is my current setup:



I run discipline and arctic armour with flame golem, plus a vaal discipline on CWDT.
For my last two gems on my main skill, I was thinking on getting Inc. AoE + either Empower or conc. effect!

My passive tree:


I have little experience in crafting my own build from scratch so go easy on me please!