I'm going to help you answer this question through an analysis of last year's results based on Fantasy Postseason's standard NFL Playoff fantasy scoring values.
Following are the top 20 scorers from last year in order:
What can we learn by looking at the top scorers from last year's playoffs?
1. The QB Rule: Draft quarterbacks regardless of how far you think their teams will go. There are 5 QBs in the Top 20 scorers, and 7 in the Top 25 (D. Brees and J. Flacco rank #22 and #24).
2. Longer not Stronger: Maintain a disposition towards drafting players on teams that are going to advance provided that they are reasonably productive. There are 6 players in the Top 20 that averaged less than 15 points per game. That number goes up to 10 players in the Top 20 if you consider players that scored an average of less than 16 points per game.
3. Hot Wildcards: If you can catch lightning in a bottle and draft players on the wild card that goes to the Superbowl you're golden. There are 6 players from the Green Bay Packers that made the Top 20 -- mostly because they played 4 games (Rodgers notwithstanding -- he's simply off the charts with a per game average of 28.90). Note that since the Wild Card was introduced in 1970 only 10 wildcards have made it to the Superbowl -- although it has happened 3 times within the last six (Packers - 2010, New York Giants - 2007, and the Steelers 2005).
4. What's a Kicker?: No kickers were able to crack the Top 20. Even Mason Crosby of the Green Bay Packers which played 4 games only ranked #23. Kickers are unpredictable -- never use early draft picks on them.