What is the next step in imporvement?

So I do tactics fairly regularly, I understand a lot of the basic tactics such as the double attack, pin, fork etc. I understand basic positional ideas when there is no obvious breakthrough looking for the best squares for each piece and getting it there over many moves make slow improvements to the position. I have fair calculation ability I suppose calculating forced mating sequences with reasonable accuracy in some complicated attacking positions. And at the moment I am trying to get more opening theory under my belt get more knowledge on playing different kinds of position and just general improvement to my opening theory knowledge so I get better positions out of the opening phase. I have looked at several theoretical endgames and I have improved in that area whole area getting more of the draws that I should be getting which helps improvement.

What is the Logical next step in improvement so right now my rapid is in the 1500's say I was looking to make it to the 1700's one day, what are some of the biggest knowledge gaps that would need to be closed for me to get there? Thanks

So Just play daily games for more thinking time?

OK for the basics (which I myself am still learning).

1) Learn chess principles (Steinitz).

2) Learn tactics.

3) Learn endings.

Master those 3 and your 1800 in not time.

If I were you I would cut down the amount of blitz and play more rapid (or daily games) instead. Playing slower games forces you to think more, and while you may not get as many games played in same time, those games you do will stick much better. Analyze every game that you play afterwards, but don't just turn the engine on. Try to see for yourself first what were the crucial moments, and if you can identify moments where you could've done something better. Afterwards you can check if the engine agrees with your evaluations. I feel like this is the most crucial step towards improvement.

Other than that it seems like you have a pretty good thing going on. Perhaps a bit more structured approach wouldn't hurt, instead of doing a bit of this and that. So maybe take one book and try to work through that, before starting another one. Do some tactics on the side and just keep playing. You'll keep improving for sure.

Someone on another discussion thread suggested a book called Chess Tactics for Kids by Murray Chandler. I bought it, and am finding it very helpful no matter what age you are.  I'm also finding Jeremy Silman's Great Courses Chess tutorials really good. There's so much stuff in chess....it's really exciting!