I have had a lot of success with it by always keeping it moving. I always try to angle it with cover so that only one enemy tank can fire on it at a time.

Cautious is an important facet to getting TDs to be successful over time. Use a radio coordinator from a command tank, or bolster the Pak Wagen's initiative the hard way to assure it shoots first, then use the Cautious roll to break line of sight if the target isn't Bailed Out or Damaged Optics by your attack. Taking the Gut Feeling doctrine will give you a re-roll in a pinch that I'd use for a critical Cautious roll. As recommended, rigging engagements in your favor also helps any tactic, especially with TDs. A Puma with Scout on-board can help you give lower init tanks final say in movement. Might also help with risky Bloodthirsty Gunner tactics.

If you're willing, I recommend adding to this list. A heavy support tank or Artillery could really help in a pinch, and there's room for improvement on both of the cars, though I'd caution against investing further into those two vehicles. Platoon Builder link

In fact, on a lark, this is a 100 point list I've assembled featuring these two vehicles with some help.
The Ambush list
The Artillery stays put, and the Pak wagen gets priority for the Scout movement boost but the pz IV long could take it if the Pak is in prime position, to set up a screen. The Pak and Artillery shoot on 10, hard, ideally at the same target before breaking sight. Watch out for woods and walls, as wheeled retroactively caps your movement at 1 when you touch terrain, even in Cautious and Blitzkrieg. "... May only make one move," specifically doesn't differentiate between bonus or phase movement that generates a token.

Edited by user Friday, December 8, 2017 6:27:42 AM(UTC)  | Reason: Autocorrect. Added content.