1.e4 e5...anything else is warm lettuce.
OPENINGS FOR BLACK (beginner)

Opening principles is all a beginner needs:
Develop minor pieces toward the center.
Castle.
Connect your rooks.
Place your pieces on active squares.

You should play the Scheveningen or Najdorf Sicilian. Spend most of your time memorizing first 25 moves, and you are definitely becoming a monster-opponent. At least with black and against 1.e4, 2. Nf3, 3. d4, 4. Nxd4, 5. Nc3 etc. Definitely one of the best recommendations for players around and under 1000 rating points. And the best argument to back up these thoughts: it's tested by top level GMs. If it's good for them, it's gonna work even better against your patzer opponents.

You should play the Scheveningen or Najdorf Sicilian. Spend most of your time memorizing first 25 moves, and you are definitely becoming a monster-opponent. At least with black and against 1.e4, 2. Nf3, 3. d4, 4. Nxd4, 5. Nc3 etc. Definitely one of the best recommendations for players around and under 1000 rating points. And the best argument to back up these thoughts: it's tested by top level GMs. If it's good for them, it's gonna work even better against your patzer opponents.
Memorizing move strings is a big waste of time for new or inexperienced players. It is drudgery that takes the fun out of the game. Understanding the principles of the game is far more important than memory games. Once they run out of memory, players are lost, drifting through unfamiliar positions.

There's nothing that rivals the sicilian against 1. e4, but for the love of Horus play something other than the Najdorf. Try the Taimanov, Four Knights, Classical, Accelerated Dragon, or Nimzowitsch.
Against 1. d4 I like the slav / triangle slav / English defense / Benko / Tarrasch / QGA. All of those are fighting responses and in an online setting / below masters I think you'll find that's the way to go. You know the line and your opponent probably is bad at it, so put him under pressure and you will do very well.

The Sicilian was invented so as to provide entertainment...for white...as he kicks it pillar to post.

You should play the Scheveningen or Najdorf Sicilian. Spend most of your time memorizing first 25 moves, and you are definitely becoming a monster-opponent. At least with black and against 1.e4, 2. Nf3, 3. d4, 4. Nxd4, 5. Nc3 etc. Definitely one of the best recommendations for players around and under 1000 rating points. And the best argument to back up these thoughts: it's tested by top level GMs. If it's good for them, it's gonna work even better against your patzer opponents.
Memorizing move strings is a big waste of time for new or inexperienced players. It is drudgery that takes the fun out of the game. Understanding the principles of the game is far more important than memory games. Once they run out of memory, players are lost, drifting through unfamiliar positions.
It's either dementia, or inability to understand when someone is speaking tongue in cheek.
Caro-Kann & Slav.
You can play them for a lifetime, even at the highest levels and they are easy to learn the ideas and pawn structures. c6 can also be played against anything.