What I should learn next?
If you are wondering what to learn next here is a chart that can help you to choose topic for your rating level.
1) 0-1000 Tactic (puzzles-pin, fork, checkmating patterns), elementary endgames (checkmating with 2 rooks, checkmating with queen)
2) 1001-1400 Strategy (improving pieces, bad piece, good piece, weak square)
3) 1401-1800 Openings, Endgames (practical endgames)
4) 1800+ Advanced strategy (prophylaxis, restriction, provocation, creating weaknesses), advanced endgames (theoretical endgames)