Help to go from normal build to crit

First to go crit you need +to crit on suffix of your weapon. Then you should play around in [POB] to see where increased damage vs crit helps you.  Crit is a multiplicative layer of damage scaling. Its something like gear damageXincreasedXmoreXcrit chanceXcrit bonus so when done right it let's you scale damage further but the other parts of the multiplicative chain matter too. Its about finding where the diminishing marginal returns to one type of damage scaling start to bite and investing more in another. That said I think there are a lot of non crit crossbow builds this league since load additional bolts is a desired suffix so some do that + levels + attack speed. Most other weapons have attack speed + levels + crit as optimal suffix. But it depends. Hope this helps 

I know nothing about shaman build, but I know I get crit chance from my weapon, atziris gloves, and vertex helm as well as skill levels from vertex. Most crit builds need a high crit weapon, because you need base crit chance. As a bm I also get cc from ascendancy, so much easier for me. The reason crit is so strong is because you can scale crit bonus very high, over 1k if you have the budget. So, higher crit chance equals more frequent critical hits and in turn those crit hits can hit much harder with higher crit dmg bonus.

I noticed some Path of Exile acronyms in this post:

• DPS - Damage per Second

^(I am a bot.) ^| ^(All acronyms) ^| ^(Suggest)

First off, you will need a new weapon if that one doesn't have any base crit chance. You can have infinity increased crit chance, but if that's multiplied by 0 on your weapon, it's still 0. Unless your skill gem itself has baked-in crit.

I would say completely come off of all your penetration passives, and those gloves. Just get a Rakiatas instead. It's one support gem that carries the load of all the passive tree investment and glove slot investment you've put in penetration. Get some gloves with flat damage and crit bonus.

Why do you have Blackflame Convenant? I must be missing something Shaman related here.. You aren't using any fire spells at all. If it's because of Crown of Eyes, then it's wrong. Just because increased to spell damage applies to attacks, doesn't make those attacks spells.

Get rid of that helmet and all spell damage nodes. They are low value and not adding much. Get rid of elemental weakness and the passive tree investment you've put into curses. Rakiatas solves this once again.
Get a rare helmet with crit chance.

You have a shit ton of investment in low value nodes by the monk starting spot. Get rid of all of those except crashing wave which can easily be connected to the travel node right above it.

You should have enough passives now to take Careful assassin and Throatseeker. They offset the negative effects of one another and provide huge value when used together.

You have alot invested in the 'echoing' passives, echo'ing frost, echo'ing thunder, etc. Which works great with the fact that your elemental damage is very evenly distributed, this is awesome. If you want to really maximize your DPS and take advantage of this, consider going trinity. Get an amulet with spirit, drop conflux,
You should be able to maintain full resonance stacks on each element.

Your ES is really high. You've invested a ton into it in your tree. I would reinvest some of this into crit and get some leech. 5k ES with leech is more than enough to survive. Dump the headhunter, and get a corrupted soul tether without the -5% ES per second mod and acquire a life regeneration mod on your gear somewhere so berserk doesn't kill you. Or socket vitality.

I have a very similar build. Rage focused, element stacking, no phys, chaos innoculation. It 1 shots pinnacle bosses, has 100% crit chance on flicker, and 500+ crit damage bonus. Idk why PoE Ninja says my DPS is 76k, it kills 15 mil HP Xesht in under a second.
https://poe.ninja/poe2/builds/vaal/character/AWMOS-1456/MK_UltraII?i=0&search=name%3DMK_Ultra

If you look at Shamans with Crossbow and Galvanic Shards, you are the second best in PoE ninja and this guy is above you with triple the damage https://poe.ninja/poe2/builds/vaal/character/Vixtor-5106/%E0%B8%84%E0%B8%B8%E0%B8%93%E0%B8%8A%E0%B8%B2%E0%B8%A2%E0%B8%95%E0%B8%A3%E0%B8%B0%E0%B8%81%E0%B8%B9%E0%B8%A5%E0%B8%A5%E0%B8%B9%E0%B9%88?i=0&search=class%3DShaman%26items%3DRare%2BCrossbow%26skills%3DGalvanic%2BShards