I took on the Bills and won the Super Bowl after year 4 (using a very fine-tuned set of sliders that makes for excellent, challenging play).
Without going step-by-step in everything I did, here's the crux of my moves:
Drafted a strong-armed, non-mobile QA in my first offseason. He took over from Fitzpatrick halfway through year 2. I used my Coach XP points to purchase the "Double QB XP Points" (or whatever it's called) and he quickly became awesome.
I drafted a stud receiver to pair with Stevie Johnson. I drafted a fast (91 speed) TE in the 7th round of my first draft -- gave myself a legit TE receiving target. After year 3 I signed Dez Bryant as a free agent, so my receiving corps was ridiculous.
After years 2 and 3 I used my 1 pick on cornerbacks, and had two play-making shutdown corners. After year 3, I signed Tom Zbikowski as a free agent to pair with Jairus Byrd in the secondary.
I drafted new, athletic MLB and outside LB.
And that's pretty much it. The Bills have a good, young, solid corps. I just took the time to groom them, fill in some holes, and it all came together.