Mana was slow for me up until around level 50 when I started getting sacred gear with better stats. Get some increased lucky hit chance, get some "mana on lucky hit", add in skills like Avalanche and the aspect that doubles it, aspect to recover mana when you use a cooldown, etc.

It all starts to add up. Lucky hit is a big one with ice shards (with piercing aspect) because it hits so many enemies. As long as there's a big group, I now never have mana issues. It's only in one-on-one fights that I'll run out of mana, but then I can teleport / frost nova / frost armour / flame shield to regain mana.