I am an experienced musician, I'm a music ed major, having studied piano for over 10 years and singing for 4 years. I have sang in a couple musicals, a vocal jazz ensemble, and a choir. I also passed my aural skills exam in college with an A.
However, my intonation can be annoyingly screwy! I always sing just a bit out of tune. I have a good sense of pitch, as I can identify pitches very easily (100% score on dictation exams consistently) but when my mouth opens it's never super great. Always a bit flat.
I was told to apply my inner ear to singing more. So that means 'audiating' the pitches in my brain before I sing them. Sometimes when I attempt this, the pitch is kind of fuzzy, which probably is the root of my problem. I was told to take a book of sightreading excercises and just read them in my head, and occasionally check the pitches out loud with a keyboard. Might take a long time to see results.
If anyone else has any suggestions or ideas, I'd love to hear it! I'm looking for daily practice tips more than anything.
Here's an example of me singing, and you can very easily tell I'm not super in tune, but it's not horrible:
Don't judge me it's a hard song!