Speaking from personal experience...
Play the level for about ten hours straight.

By this time you will have become one with the game. You'll know exactly where the tanks appear from, exactly where enemy soldiers appear, exactly where the med packs are (although this isn't much use if you're playing on the hardest setting

), and with a lot of luck you'll make every shot count, panserfaust or otherwise!
Mneh, that's not much use...
...as far as tactics go, use cover. Alternate between the bunker and the house beside it (or more exactly the wall behind the house which is low enough in one place to allow you to take out two of the tanks - but be careful as enemy troops hop over this from time to time). Keep a sub machine gun armed at all times except when engaging the Panzers.
But trust me, stick with it! After a while, a long while, you'll enter into a sort of spiritual rapport with the game and when you beat the level you'll be left thinking "gosh that was easy"
Then you'll mince the rest of the game, and have some good skills to bring online!
Always attack to defend, though... I don't know how many times I got caught with my pants down, cowering in a corner thinking I was safe. Don't cower! Let enemy corpses do the cowering...
Play It Cool
-Moog
PS: I was at the site of the real Pegasus Bridge this summer after having played the level on Call of Duty. It was strange how much I knew about the real place just from playing the game! Also, the owner of Café Gondré threatened to call the police because my step-father refused to pay prices that weren't printed anywhere. IIRC a simple crèpe cost about €12... we were a hungry family of five so you can imagine the cost of a 'light lunch' times five came as something of a surprise seeing as there was no indication of cost prior to receiving the bill.