The typical straightforward way to improve is to play Daily and/or longer Rapid games like 15|10 or longer. You need time to think through positions. Then you need to analyze those games and determine the mistakes you made and why you made them. This will help you determine what aspects you need to study the most.
Additionally, it always helps to learn and improve your ability of the opening principles, which can be a great guide in any game, and eventually learning the ideas of select openings.
One thing you’ll always want yo be working on is your knowledge of tactical motifs and finding them in positions- solving puzzles helps greatly with this. I recommend daily doing at least a few, but the more the better. You’ll improve the fastest by becoming proficient in this.
It doesn’t hurt to have a basic grasp of endgames- elementary checkmates, promoting pawn with king assisting, triangulation and the square of the pawn, protected passed pawns, pawn majority and minorities, and basic rook endgames.
Have a great chess journey!
I've had this account for a year now, and my rating is 690-750. With my rating once being at 300. Only now I've been playing a bit more seriously. So my question is, am I bad at chess?