How can I improve my character?

My character: https://www.pathofexile.com/account/view-profile/TehBoomer/characters?characterName=Swisscheesesandwich

I'd like to be able to take off the Kikuzaru ring, but it causes me to be in a negative HP/ES regen when RF is active. What can I do to increase my ES regen even further to be able to equip a better ring?

I am mostly, with some exceptions (some things that this guy has seem to be unavailable in the current league), following this guide:

https://www.pathofexile.com/forum/view-thread/1816656

Lastly, this is my first time trying a build like this. First LL. First ES/ES regen. First RF. Etc. Any other advice for where I can improve my character would be greatly appreciated.

Hi Exile,

you have chosen one of the most expensive and rather complicated build around.
Are you familiar with Path of building? (if no download it and upload your character there).

You gear is lacking lots of ES (you can find out some top end gear in the guide)
If you can´t afford expensive rare items try to search for alternatives.

Helm - The vertex - put auras and enlighten there
Belt - you want either Crystal belt with recovery rate or Stygian wise + abyss jewel (flat ES, regen, …)

Gloves - Shaper´s are fine but wrong corruption is not (you want +1 skill eventually) Good rare gloves are better anyway. Btw you can´t use both auras with BM anyway (what auras do you use?)
Boots - Delusion boots are fine if you can´t afford lvl 23 purity aura otherwise (unset ring +2-3 skill + lvl 20-21 purity of fire)
- Sin Trek are cheap unique boots (if you don´t need res)

rings - you want high ES, intel, res you missing

Take Influence passive to boost your auras.
Upgrade your flasks - you don´t need life flask, missing useful mods (anti bleed, freeze, shock, curse).