Even though the playoffs started last week, if your team has made it this far there is one thing you need to do... put out your best roster for each game. If you don't you might end up losing when you really shouldn't have.
In order to put out your best roster there are a few keys you need to look at and do before you start one of your players.
1.Who are they playing? Look at their schedule. For instance, let's say one of your running backs is playing a tough defense. If this is the case you might want to start someone else in his place. (this year Mark Ingram vs the Arizona Cardinals Defense)
2.(not referring to quarterbacks) Are they the number one for their team? Is the player the most targeted or gets the most rushing attempts on the team and are they the go to guy on the team? (Jordy Nelson, Antonio Brown, Desean Jackson,Demarco Murray, Frank gore, Greg Olsen, Jimmy Graham, etc).
3.How have they been doing recently statistic wise? Consistent, inconsistent, High scoring, low scoring? (Jay Ajayi's last 3 games scored only 5 fantasy points and plays a decent jets D).
Once you have looked over these three keys, they'll give you who should start for the playoffs based on who is on your roster.
So remember to choose wisely these next few weeks, and good luck.