To actually start improving you'll first need to know the endgame, then the middle game then opening. That's how it is instead of doing the opening in the first. I agree you need to know the basics of the opening but that's it. Don't get greedy in the beginning, just focus on developing the bigger pieces, the pawns and then try to attack from the king side or the queen side. If you have any questions feel free to ask me.
I think middle game is most important. If you know opening principles, then focus on middle game skills. Then, learn endgames and some specific openings.
Actually, another note: dont focus on developing the bigger pieces. Knights and bishops are good in the opening and middlegame. Rooks are only good after you castle, and after a few pieces have been traded down.