Slark

As you load into the game, start running to scout opponents placing wards as you have night vision.

Hit an opponent whenever you can to create a damage difference of 4. It'll help you with lasthiting.

If you are able to build up a few Essence Shift stacks, you can perhaps commit for a kill attempt with Pounce.

Play more aggressively during night time as you have increased vision.

Whenever you are in trouble, you can Pounce away or even Shadow Dance and teleport out.

Pick up a couple of sentries to deward when you sense with Shadow Dance you are being seen.

Whenever you have a decent amount of Essence Shift, play more aggressively and look for extra kills.

Whenever not much is happening, push out the sidelines as Slark is quite elusive.

Slarks aghanims shard is very good for man fighting and saving allies, consider purchasing after your 3 main items.

Slark tends to do well against offlane melee due to Essence Shift stacks. Check if you can send at least one ranged hero against him

Place wards in unusual spots and more defensively as Slark is able to sense vision with his ultimate

Keep an eye on Slark's Dark Pact usage so that your spells and items don't get dispelled

Force Staff allows you to break away from Slark's Pounce

Slark has increased night vision so he's likely to spot you before you spot him. Use Smoke of Deceit to gank him more effectively during night

Long fights are favoring Slark as he is able to acquire Essence Shift stacks. Keep an eye on it and avoid fighting him if his stacks are high

Instant or near instant disables and burst damage are good at dealing with Slark