Your priorities are taking advantage of
Stalking Panther above all else. At a minimum shoot for 21-22k evasion. With this tree and T1/T3 flat evasion or hybrid rolls you should hit this number and can gear up progressively better from there. Grabbing a magic T1 base and using a single Essence of Greater Enhancement is enough to get started, fill out resists on rings/amulet then improve your gearing from there.
Seriously, don't skip evasion or you will die. A lot.
Mana
Lavianga's Spirits can make mana a non-issue. I'd recommend acquiring one if you can provided they don't get expensive. It's amazing to have an additional constant mana regen source. Otherwise you'll want to get a % mana on kill jewel or invest in some mana regen somewhere on gear.
Soul Tether
Soul Tether, when Vaal Incursion Corrupted to remove the bad downside of losing 5% energy shield per second, is INSANE for recovery. With a single attack you will completely refill your entire HP and ES pool. Highly recommend if you have a few extra divs. It's a very common unique and my experience corrupting them is about 1/10 end up usable, though I acknowledge that's a small sample size.
Hat
Maximize Evasion as much as possible, and consider an additional Deflection roll suffix. If you are just getting started you can grab a magic
Freebooter Cap with T1 flat evasion and Greater Essence of Enhancement on it which will give you a roughly 1000+ Evasion starter hat.
Boots and Gloves
You want hybrid bases here as flat Energy Shield is in short supply.
Voll's Protector was buffed this patch and provides about 100 more flat ES, but your main source of it will come from your boots and gloves. Just like with the hat you can grab a magic
Freebooter Cap and Greater Essence of Enhancement for a pretty solid starter kit.
Jewellery
Life, Res, and at least ONE T2+ mana roll to support your Whirling Slash mana costs. You'll also want one life leech node somewhere on your gear. Your rings (or gloves) are a great place to have it. Flat damage is also welcome once you start min-maxing your setup.
Spear
You want two affixes on your Spear. T2+ Critical Strike Chance and T2+ Attack Speed. The only other mod that is nice to have is Life Gain on Hit. This is just a critical strike generator.
Quarterstaff
Big damage. Lightning is first priority. You can deterministically craft a very good GG quarterstaff, I'll link the video here, or you can find instructions on how to craft it in my discord (in the video description on the sidebar)