How to get to 2000 ELO rating I'm a 1800 chess player.

I know pretty much all the basics in every fields of the game.

I know the main lines of openings, I know tactics, I know end game. Average in all of it (=1800 player). I would say I'm a little bit more of a tactic player though.

I know that I need to study to get to 2000 which is the dream for me.

My question is:
What would be the best things to train to really get to 2000 ELO without too much work?

Should I become a tactical beast and just learn easy openings?
Should I dig deeper in all openings (which is a pretty big work)?
Should focus on finals?

I know all of this important, but it's a lot of studying for these 200 points I'm missing. I really wonder if there's a shortcut to reach just 2000, I don't plan to become a master with all the knowledge needed for that.
The best thing to train is (almost) always calculation:


Get a set of maybe 1000 3-5 move combinations and go through those problems until you basically know them by heart. That's to enable pattern recognition.
Apart from that set, concentrate on calculating long variations in your training instead of just seeing tactical shots. The Yusupov books are a good source. 
Maybe try to learn to play blindfold. That demands a lot of concentration and improves your visualisation


The next best thing to train is positional understanding: 


Play tournament games against strong players.
Analyse these games with strong players.
A big part of positional play is connected to typical opening setups. So if you spend time on the opening, spend it by learning about typical ideas.
This Aagaard book I liked.


I wouldn't worry too much about the endgame or the opening. Good endgame play builds on strong calculation, good opening play builds on positional understanding. Just learning stuff by heart without having this foundation is not going to benefit you much. And the essentials you'll probably pick up anyway.