Whoo! First time I've manage to actually carry as Trax. 33/9 ain't bad for me, especially with how badly that game was going at the start.
So, how to Visage?
Pick him in a lineup with a lot of early game burst. 1 point in each skill, max soul assumption then q, then his e, picking up ult at 6/11/16. You can max his passive over his q though if you are facing some really tough gankers.
The meat of his game is soul assumption. At max rank you can store 6 (starts at 3, gains 1 max charge per rank) soul charges. Whenever a hero within a certain radius (it's large) takes 110 damage you gain a charge. Doesn't matter if its your heroes, yourself, the enemy or who is dealing the damage (could be creeps). So what you want to happen is immense burst damage and then to release your nuke.
The second part of his game are his familiars. They are a long cooldown summon that lasts forever when summoned. They have low health and armor, a ton of magic resists. They hit hard but each time they hit they lose damage. They have an active skill that turns them into stone form which stuns nearby enemies and heals them/reactivates their damage, they come out after 8 seconds (I don't know if this intended or not but they don't seem to be affected by Siren's Ult or Blackhole). If they die the enemy gets 100 gold for each of them, so be careful with your micro.
You would open up with your gargoyles (they can also fly like the courier/bm hawk can, so they ignore terrain), snare the enemy, wait for max/high soul charges, soul assumption. Once your gargoyles attack damage is used up, stun them, then try for one last soul assumption if they aren't dead by then.
There's a visage guide on playdota I'd link to you but the site is timed out right now.