OK, first of all, what do you play?
Try not to focus on bullet or blitz games. Rapid and daily may help.
That's okay, if you make a lot of mistakes. Keep analyzing and watch videos on chess.com. Then, use those themes to play some tactics. Your rating will grow gradually.
When you see some boards on chess.com, analyze it to see what is a blunder and what's brilliant.
OK, for chess.com memberships:
If you want something that is cheap, go for gold.
For platinum, it gives you a little bit more for a little more expensive price.
And for the most popular, diamond, gives you ALL the features, but is expensive.
For me, I chose diamond. It's great! You get all the features.
The BEST would be platinum, most of the features for a more expensive price.
If you want to improve, read chess books by famous authors, for example, Jermey Silman, Susan Polar, and more.
Thanks, and hope this helps! 
GM_chess_player
hello friends
im beginner player and i need advise to improve myself in chess , i dont know where to begin my steps
i ask myself do i have to stick with playing chess and analyze my games although i have big problem with puzzles i cant solve puzzles easily and i do a lot of mistakes .
and i have another problem some guys share moves for example moves for carlsen and i read comments like what a wonderful move, and when i see it i cant understand why this move is wonderful it is silly so i am disappointed i love this game but i want to improve very quickly .
finally i want to ask about the premium membership what is good for me gold , platinum or diamond membership
so please help me and give me tips or a plan to stick with it to improve myself and thank you