Hi,
Welcome to the site.
The top players make these great scores by practicing, have a look at the top players stats and you will see what I mean. You have played a handful of ranked rounds which is a good start, but the top players have played hundreds of ranked rounds. The top player has I think played about 800 ranked rounds - OK ??
How to get better easily ? It is very very simple - PRACTICE !! With practice you should improve pretty quickly, then the better you get the harder it gets.
From your stats you are doing very well, seeing that you have just joined the site.
There is a lot of great info in the forums that can help with your game play, so please check it out. Use the search box top left and enter key words.
All the best, and most of all - have fun.
Cheers Doug