on your Skull, replace the +5000 Fire Dmg (Epic-Orange) with +100% WD (Epic-Orange). you will see an increase in Dmg.
your Eternal Items are wasting space with unused or unneeded affixes. it looks like you are using Skull Shield to do all the damage, so the Eternal Nadroji is wasting space with Blind Resist and Specialist. the Eternal Frostfire, well, Sword doesn’t have Meteor, so Aftermath Set and Bonus, +18 Meteor and the Meteor Proc are useless, unless you are pushing the button for one of the MH Skills to activate the Meteor Proc. if you are doing this, change either the Crit Chance or Crit Dmg to +100% WD (Epic-Orange) so your Meteor is causing more damage. the Eternal Fire Storm needs 3 Crushing Flames Items to be activated. also, you have more items shown than you have space for on your Character, so it is hard to tell which Items you are using and which you just want advice on.
any +5000 Fire affixes can be replaced with Dodge until you get up to +60%, then put in Crit Chance, Crit Dmg, or Deadly Strike if you have enough of the other two affixes.
if you are trying to farm for more Crystals, do a Search 
on Farm Builds to get an idea of what you need. max Gold Find and Luck will help a lot. the Crystalline Set can also help even more. the best floor to farm for the Ultra Rare Crystals and Myth Stones is floor 501 to 510.
the Nadroji Bonus Affix (Grey, Light Green when activated) increases the Spawn Rate for Magic (Blue) and Rare (Yellow) monsters by +100%. they drop more Loot than the Normal (Gray) monsters. it’s up to you if you want this on your Farm Build or not.
Epiphany Set increases the Cap of Affixes by +5% per Rank. so Epiphany (5) would increase the cap of Dodge from +60% to +75%.
the reason i said to have lots of Gold Find is because you can Convert Legend & Eternal Items to Rare and Ultra Rare Crystals, but it costs lots of Gold, 245K for the Legends and 500k for the Eternals. also, you can upgrade 2 of a lower Crystal/Myth Stone to the next higher Crystal/Myth Stone. it only costs 1 Crystal/Myth Stone if you want the next lower one. this also costs lots of Gold.
since you are a Newbie 
, I have to say are doing well to survive on floor 500+ on M3 with your Skull Shield. save a map of the floor you are on, and go to floor 200. then work on making a Farm Build with max Luck & Gold Find. it would be better to have the Nadroji Robe, it has the Bonus and +100% ED, which the Nadroji Hat does not. i used that on my Farm Build. when you feel that you are ready with your new Farm Build, use your floor 500+ map and start farming. always buy a map of the floor you are farming on, or you will keep going up the floors and end up on a floor you can’t farm because you are dying all the time.
welcome to Dungeon Quest @ZuBlack , i hope i was able to help you a little.
