Overview
Julian can be mid lane exp lane and jungler he is good for 1v1 the enemy and could easily burst squishy hero you need to master his skill enhance to be very vulnerable in teamfight
Strengths
Julian is strong at poking outplaying hero and bursting and he's fast to clear waves jungles creeps and buffs and could solo elemental lord and turtle with a right build
Weaknesses
He's weakness is high sustain hero with damage and burst hero like kadita and etc and he's kinda useless for teamfight due to lack of sustainability
My usual build
For high bursting and fast farm and more likely overkill for marksman in basic attack in late game due to high damage skill with immune or crowd control but you could change build depends on the hero of enemy and gameplay
High lifesteal
It's op for sustaining damage if enemy have less crowd control and anti lifesteal because not many all buy it like they didn't know anti heal exist so it's good for that enemy but this build are kinda risky due to lack of skill damage and weak for burst enemy
Sustain like a tank
Good for sustaining if your team have damage roam like helcurt saber kadita etc but it's kinda useless for bursting enemy and 1v1ing enemy dues to lack of damage only sustain and medium damage but it's still op for teamfight
Mage
You can also use fighter emblem or assassin emblem but this is I recommend because of the +penetration and cool down reduction and partner it with rupture and seasoned hunter for fast farming and war cry for instant burst and high damage for 6 seconds
Battle Spell
It's for the jungler to farm easily and could easily secure objectives due to high burst damage
1v1ing enemy or ambushing the enemy
Julian are good for surprising enemy squishy with he's combo of enhance first skill and 1v1ing enemy but be cautious of using skill Julian still vulnerable for burst enemy and hard crowd control
Best With Gusion
You could just damage his combo if you fully mastered Julian with he's untargetable 2 enhance skill
Watch Out For Ling
U could just dodge his ult so ling will be have a hard time dealing with julian