Keep faithful and pray!
Exactly—that's the main thing. And the Bible commands us in Psalm 37 not to fret because of evildoers who prosper. But what percentage of posts on FR could be classified as "fretting"? Sadly, a very high percentage, it seems. And defeatism and an attitude of "doom and gloom" are not Christian.
Anyway, God says not to engage in that kind of behavior, but rather to commit any problems we may face to prayer. I'll close with a few encouraging scriptures for us to focus on:
"In this world you will have trouble. But take heart! I have overcome the world.” (John 16:33)
"This is what the Lord says: Do not be afraid! Don’t be discouraged by this mighty army, for the battle is not yours, but God’s." (2 Chron. 20:15)
"Do not fret when wicked men seem to succeed! Do not envy evildoers! . . . Wicked men will be wiped out, but those who rely on the LORD are the ones who will possess the land. " (Ps. 37:1,9)
"Do not be anxious about anything. Instead, in every situation, through prayer and petition with thanksgiving, tell your requests to God." (Phil. 4:6)