Bhav
I could have just been a piano teacher / tutor.
I spent a very long time with sight reading practice books and loads of sheet music, but Ive never been able to read and play without requiring ages to figure out each bar of music.
I had trouble learning to sight read until I took singing lessons. It showed a technique that was totally unexpected.
As a guitarist, I would read "that's an A, that's a C#, that's an A again, and that's an E." Easy, because the frets on the guitar show me where A, C#, and E are.
As a singer, I had to find the A, and then go "up a maj 3rd, down to the root, then up to the 5th."
Now I can sight-read for guitar (mostly) because I find that first note and then focus on the spacing as opposed to the actual note. I found it much easier to see that going from one space up to the next was simply jumping 2 semi-tones.