Juggernaut is a melee agility carry that excels in the early and mid game with strong damage output from two of his active abilities and strong synergy with pushing line up thanks to his Healing Ward.
He does somewhat scale off in the late game, so it's best to push your advantage early.
Skills
Put a point into and max Blade Fury first. Try to combo it with a lane support with a stun for kills early on.
Get two points into stats optimally.
Get Omnislash at level 6, 11 and 16. With the two points into Stats you can perform your full combo (Blade Fury & Omnislash) for easy kills.
Next get a point in Healing Ward. You can get this earlier if necessary to stay in lane. If you don't need it in the lane get it for when you push and for teamfights.
Level and max Blade Dance next, then finally max Healing Ward.
Items
Starting Items (easy lane): a Healing Salve, a set of Tangos, an Iron Branch and 2x Slippers of Agility.
Starting Items (in a competitive lane): a Healing Salve, a set of Tangos, Stout Shield, and 2x Iron Branches.
Early Items: Phase Boots, Magic Wand, Poor Man's Shield.
Core Items: Drums of Endurance, Aghanim's Scepter.
Luxury Options: Desolator, Manta Style, Shadow Blade, Assault Cuirass, Abyssal Blade, Butterfly, Monkey King Bar, Boots of Travel.
Situational Items: Black King Bar, Diffusal Blade, Vladmir's Offering.
