Welcome to this Vaingloryfire build!

Its my first time writing a build, so it might be ****py, nonetheless, I hope you like it :)

Please do leave comments, I appreciate feedback greatly.

To pick or not to pick? Well, Here's a overview of Joule (imo)

Pros
-2 Nukes (Playing CP)
-Sword to melt enemies (Playing WP)
-Tanky late game with perk, can 1v3 if well farmed
Cons
-Ulti easily countered with Slumbering Husk (CP)
-Squishy without attack speed/damage
-Can be hard to fight enemies late game if both sides are well farmed. (fast attacking enemies/large damage output nukers)

Weapon or Crystal?

You should choose weapon when:
-That instapicker wants to play Crystal (jk)
-Enemies can easily escape your ult (Vox/Glaive/Idris etc)
-Enemies are more tank and ult doesn't finish them off
-You just wanna go whish whoosh and kill ;)
-You like to watch enemies die slowly/at your feet (just a prank)

You should choose crystal when:
-WP instapicker!
-Squishy heroes (Ringo/Kestrel/Celeste) (ez food)
-You just wanna erase people off the battlefield with a click of a button
-You are too lazy to chase/aim stun to attack people with WP

Pros of Weapon:
-Less likelyhood of Enemies escaping
-Fight without worry
Cons:
-Diving too deep = Death
-No attack speed = Not enough damage output

Pros of Crystal
-Easily engage from far with ult
Cons:
-Ult on CD= Main damage output not available (If you get dived on by heroes like ringo/glaive/saw/harambe[ozo], your fk*d since they can deal damage to you faster than you can to them)

Alright, time to play the cleaner,

If you feel that you can survive well in team fights, then go ahead and exercise this build.

With this build, it will be easier for you to turn fights around!

Skills:
-Since we are playing weapon, we would ofc prioritize damage over the stun.
-If you are feeling brave, feel free to skip ult to level up stun earlier for the lower cd.
-Possible to overdrive stun if you want to engage hard-core/have higher chance of escaping(Low CD) (Try at your own risk)

Items:
-Starting:
We want the two weapon blades to clear jungle fast/ harass enemy laner for free space.
You can opt for light shield/armor if you are scared of taking too much damage early on, or if you want higher sustainability.
-Can buy either 3 potions / 1 potion 1 trap if you choose to buy defense item.

Early game
-Getting damage from Sorrowblade, for attack as well as 2nd skill.
-Boots to chase
-Reflex Block is optional, if no stuns/nukes item can be skipped. Same for armor/shield upgrade, if you don't take too much damage you can skip those items and go for more damage.

Mid game:
-Tornado Trigger for attack speed
-Breaking Point for attack speed + more damage

Late game:
If you skip defense items, then you have 5 slots for items in total, so you can buy a monocle as well as an extra tornado trigger for even more attack speed. If you do buy defense, you can choose between Monocle(Hit harder) or a Trigger (hit faster)
-Journey Boots for chasing people down

When you wanna play safe, this is what you should improvise with.

Skils:
Almost same as the Weapon, Fighting build, just that we choose to take an extra level for Rocket Leap early for a lower CD. (You can follow the B B A B B [skill number, A-Leap B- T.Strike] build if you want to.

Items:
-Instead of going for Sorrowblade, we choose to go for a Serpent mask first so that we can get lifesteal and survive longer.
Starting Items:
-You can either opt for Book of Eul. for the extra health after killing creeps OR defense. It's up to you. Same goes for potions/trap when buying defense, either 3 or 1:1.
Midgame:
-After getting your Serpent Mask, you can either go for a Sorrowblade to hit harder/Trigger to hit faster.
Lategame:
Since we are opting for survivability, we choose to buy some defense. Armor is optional, if you can't tank the enemy weapon carry/jungle, then buy a jacket(if your team already has someone who bought a pauldron) or a Atlas Pauldron.
-Breaking point for the extra attack speed to lifesteal faster, as well as hit harder.

Self explanatory from title, you just wanna nuke.

Skills:
-Since we go for Crystal to nuke, the stun offers more damage, as such, we choose to max it first.
-We are aiming to use ulti as our damage output, so we do not prioritize T. Strike.

Items:

Starting Items:
-Crystal Bits for the damage
-Halcyon Potion in case of emergency

Early Game:
-Shatterglass for that extra damage to start your journey into erasing people
-Reflex block optional, it's up to you. I'd you want defense, you can choose reflex blocm
If you want more damage, skip it at a cost of potentially dying. HOWEVER, do not skip if enemies are stunners as they can cancel/prevent you from using ulti.

Midgame:
-Frostburn to keep people in you ulti (You can also choose to buy this first then but shatter of you feel that people run away from your ulti too easily)
-Broken Myth for more damage!

Late game:
Can either choose to buy 2 defense, or 1 defense and clock/echo or no defense, clock + echo.
I would buy echo only if enemies buy a slumbering husk. (It's annoying to see your first ulti go to waste with a slumbering husk)

You still like the idea of chasing people and making them fall at your feet, but your teammate is playing weapon? No fret, we have this 'alternate' (no pun intended hehe)build.

Skills:
We are fighting, so it's somewhat like the Weapon,Fighting build, just that we go for extra levels for Rocket Leap because we are using CP and this provides more damage.

Items:
Starting:
We are fighting, so we buy a crystal bit for damage, and a swift shooter to hit faster. You can buy 2 crystal bits if you wish to.

Early game:
-Whats playing CP, Fighting without a alternating current? (duhh)
-Can get reflex block as a optional item (you're probably tired of me saying this)

Mid game:
-Aftershock is optional, but it will help you to deal extra damage with you normal attack after you use leap/T.Strike
-Frostburn will help you chase up with people as well as ensure you get hits on them and they don't run away.

Alternate(NO PUN!) Mid game build:
-If you feel that you cant get hits fast enough, you can then swap the Aftershock for a tornado trigger. Doesn't hurt to spend 100 extra gold.

Late game:
-Shatterglass for extra damage when hitting, as well as damage for ulti. You can buy this first, swapping out aftetshock/Trigger if you really desperately need damage.
-Aegis as defense, you can avoid buying aftershock/Trigger if you need some armor, the shatterglass should make up for that missing damage, you also still have ulti.
-Halcyon Boots for more mana.

Some extras, might help you sometimes

-It's always good to 'foresee' the enemies path, e.g watching which direction they are moving so that you can center the stun. Try to use it in front/behind the enemy to ensure a sure stun. This takes practice so don't worry!

-Chain your thunder strike as often as to u can. The bonus armor/shield pierce buff really makes a difference.

-Try to tap behind heroes when using your ulti for a more accurate shot. If enemy is too far and you will reveal yourself trying to tap behind them, tapping a little in front of them also helps.

-Don't panic/overthink while playing joule, this potentially messes up your skill placement.

Friends:

Stunners/Rooters(Catherine/Ozo/Glaive/Lance) on your team are your best friends as they can help with your skill placement.
*Lance/Glaive might mess you up, so it's best to wait for them to use their push before you use your skills.

People with slows are also your friends!

Foes:

Heals, (Adagio/Lyra) can be detrimental to you, as that little bit of extra help might help enemies escape from your attacks/ult.

Stuns(ref above) can also stop you from chasing/using ulti.

Invis heroes (Flicker/Taka) catching you off guard makes you have lesser time to place your spells properly.

Items, mainly slumbering husk, crucible, aegis, all of which gives barrier/health can allow enemies to survive/make a clutch escape.

Hope this helps, it's just my opinion of how to play /fully utilize Joule.

Everyone has different opinions, so this might not be a perfect build.

Just to recap, I hope this helps!

-Leave comments pliz, I luv feedback, good/bad-