This build for Sylvanas focuses on playing her as a pusher without sacrificing too much teamfight ability. This build will allow you to wipe out large waves very quickly. This is accomplished by casting Haunting Wave to get a wave low health, then spamming Withering Fire (Q) to finish the mobs off one by one, causing them to explode on death (from Unstable Poison T3 passive), clearing the wave and refreshing your Withering Fire (Q).

Any damage dealt by Sylvanas via Basic Attacks and Abilities applies her Black Arrow trait, stunning the target for 1 second. With the Paralysis T2 talent, this duration is extended to 2 seconds. With the Unstable Poison T3 talent, enemies that die while under the effects of Black Arrow explode, dealing 84 (+9 Per Level) damage in a medium area of effect.

1. Check enemy positioning
2. Approach Wave
3. Cast Haunting Wave on as many creeps as possible
4. Get in range, and spam the Q key to cast Withering Fire
5. Check enemy positioning, and retreat if unsafe

The most important part of this build is to use proper caution. You'll be able to take out a wave very efficiently, and the temptation arises to over-extend to grab "just one more wave." Map awareness is key! If you don't know where the enemy team is, don't go for it. As a general rule, you don't want to pass 1 section beyond your furthest surviving fort without knowing the enemy team is a sufficient distance away.

If you need to clear a wave for strategic purposes, I recommend using Shadow Dagger in place of Haunting Wave, so you can save it for an escape.

Things will go wrong when you're pushing during mid game. An enemy will appear where you don't expect them, your allies will leave you behind instead of helping you survive a fight, et cetera. You have 2 key abilities/passives that will help you escape:

1. Haunting Wave - Reuse this ability while it is in the air to quickly dash to the current position. This allows you to phase through walls and barriers. Use wisely!
2. Evasive Fire (T2 talent) - This ability gives you 10% movement speed (stacks to 30%) when you use your Withering Fire ability. Use this ability up to 3 times while running to reach maximum move speed. Use the remaining charges tactically to maintain your speed before it reverts to vanilla speed.

If necessary, you may use Wailing Arrow to silence a caster who will kill you if they cast another spell. Bear in mind that you will lose your lead by taking the time to turn around and cast this spell.

This guide is a work in progress. If there are errors, typos, or omissions, I welcome constructive criticism. This is not meant to be a high level guide, simply a beginner's base of information to be an effective pusher as Sylvanas.