Watch the Band of Brothers series, especially the assault on the guns on D-Day.
Use cover, get close, use the mortors for smoke or to pin the unit you want to assualt.
If yoiu can get a section of thses guys into h to h, you will rip them to bits.
Also if you have the points, LMG's are good to attach to your combat squads for defence, and can be used to soften up your target.
If you dont go for armour support, and depending on the Mid/Late war lists, go for as many bazookas as you can afford. They WILL take out a Tiger if you have enough of them.
Light arty( 75's) is not too bad but take the max you can afford for mid war. Late war you get the lightweight 105's as well. Less range but still effective.
For armour, the M10's have the punch, but really easy to kill if you cant get you head around the tank destroyer rules.
Shermans are ok, but you need a few of them.
Caverly recon is good at mid war, White scout cars are gun buses, you will mow infantry down, late war, the 37mm gun on the recon wheelie is great against apc's and trucks, and a lucky shot can bail out medium tanks. A really lucky shot will brew 'em up. But don't bet on it.
Also they can dismount if you are defending, so you get some more gun teams, mortars and zooks. Did I mention take lots of zooks.......