first conclusions to get to 1900+

As long as there are 4 players on the board, better help your frienemy (opposite player) to win and finish 2nd then him being killed and you will be the next to be attacked. 

Don't start too aggressive cause you will be vulnerable, nor too passive cause your frienemy will be. Queening fast is not necessarily good for you, well protecting your king is.

Your worst enemy is the one closer to your king.

Don't exchange unless its very good for you and don't let others to have the option to exchange with you.

Yeap, good advices. But after having achieved the 1900 goal, you'll find that it's more fun to play more recklessly.

Players dont reach 1900 nowadays.

Hard to go to 2000 cuz they simply don't play, just to be on the leaderboard.