Having not seen specific games, here are a few things to think about when you play against aggressive openings you are unfamiliar with:
1. Developing pieces and controlling the center are generally good ideas. But don't forget king safety. Get your king castled early!
2. Look for ways to trade pieces. The fewer pieces your opponent has, the harder it is for them to attack.
3. A very aggressive opening almost certainly means your opponent will have holes in their defense. Watch for those and find opportunities to counter attack.
What’s the best way to counter these odd, aggressive openings? How can you prepare for every possible opening? I develop my pieces, try to control the center, but against these openings I get owned.