One of my standard opponents is a fellow named Ludvig. Ludvig plays Imperial Guard, so I can be sure that I'll face a lot of tanks when we play. Today I will share a tactic that proved very useful to deal with tanks, and won me the game!
Basically, it's a decoy unit soaking up fire until the hard-hitters can get in close. As decoy I used a Furioso Dreadnought, and five Terminators with Storm Shields and Thunder Hammers as my hard-hitters.
The Furioso is a great decoy! Not only because it has a high front armour value, but because it's a big threat to tanks itself! If your tactic fails, just send him on a killing spree.
First thing I do is to deploy the Furioso's transport; a Drop Pod with a locator beacon. Since the Drop Pod has a very secure way of Deep Striking, just place it as near your target as possible, but try to stay within 12" from the table edge, as it still can scatter off the table. The Furioso has a high threat level that the opponent won't even think of targetting the Drop Pod (unless he gets a lucky shot and kills the Furioso right away...). Send your Furioso to deal with the closest target.
In turn two (or as soon as they are available), Deep Strike your Terminators within 6" of the locator beacon. Send them off in another direction to maximize the killing zone. Their Storm Shields will ensure that they survive the incoming fire the next turn. Their Thunder Hammers are great for picking out tanks. If they fail to destroy them, they will at least be stunned for the next turn.
Should this fail, should the Furioso and/or the Drop Pod be destroyed, then deep strike them anyway! The Drop Pod is only for precision, but not necessary.
Do you feel that your own lines are threatened? Make sure you equip one Tactical squad with a locator beacon as well, and you will have an instant Termie-wall.
That's it for me for this time!