There is no exact difference between a 1600 and a 1800. Chess involves a lot of different skills, and one player may be much better at skill X and worse at skill Y compared to a player of the same rating. It's all a continuous scale and an 1800 will be better on average than the 1600.
In a chess game, the most important skills are to be able to make a plan based on any position (evaluate who is better and why, what the goals of each player should be, and what good moves are to accomplish that) and to calculate concrete lines and find tactics for both players.
What are the traits that set an 1600 and 1800 rating apart? How can I make the jump?
I've listed a few things I've thought of, but don't know which deserves the most focus in this skill rating range:
Experience - Is it just a matter of continuing to play games?
Knowledge of Openings - Should I be memorizing openings?
Board Awareness (seeing 2, 3 moves deep) - Should I be taking more time in games to get a deeper understanding of each game?
Any thoughts?