Ummm need some more specific questions on what kinda strategy you need...there is no golden path to greatness in Madden...you can't just name a "general" strategy.
For me, on offense, you should strive to reach a balance between your runs and passes. Even if your running game isn't going, you have to keep running it to keep the D honest. The easiest way to win in Madden is forcing the other team to play 1 dimensional. You need to keep your offense on the field as long as possible, running the clock and mixing it up.
On D, you should mix it up early and often to throw off the O. Try many different things, such as tight-man-to-man-blitzing, loose cover 2 zones, zone blitzes, 4-3, 3-4, etc etc. Find something that works well, then stick to it.
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[color=green]PS I'll find my frog[/color]