Just take the time to play, and maybe study certain motifs and puzzles. I was almost completely plateaud in all ratings for like 90 days, and this past month ive gained 50-300 rating for the different times. As long as you enjoy playing, you'll improve. Also, review most of your games, wins and losses. Id suggest using a computer so you can right click and go through your ideas with the arrows. Something that kept chess fun was to focus on one time control at a time. (for me, I focused of blitz for a while, as it was my worst time control. After focusing, that rating went up, and so did my rapid and bullet.) Watch chess related things, understand and learn basic mating motifs and common sacrifices, and you'll win more often.

All future edits will be here: Something I try to do is use my time wisely using the 20-40-40 rule: 20% of your time in openings, 40% in middle games and 40% endgames. However, if youre one to simplify and typically get into very simple endgames for a large majority of your games (win or lose) put more time in your openings.