Some leagues give you a small scoring advantage at certain positions, intentionally or unintentionally. The scoring system at quarterback could be greater than at other positions. If that is the case, you know you will need the best quarterback available immediately. This applies to all positions. Knowing the scoring system will also help you determine the kind of player you want on your team.
Some leagues give bonuses for number of completions, rushing attempts, and receptions.
If that is the case, look for players at these positions who have higher amounts of these actions than others. On the other hand, some leagues give negative points for interceptions. The only special teams points that are allowed usually is for kickoff returns for touchdowns. I would not invest too much time into knowing what team dperforms the best in this area. Most fantasy leagues combine defense and special teams.