As many notes on an NSP chanter can be bent about a quarter tone without putting the drones far out - at least on a good reed day - I guess one difference between a good piper and a fairly good one is the former will squeeze notes into tune unconsciously and accurately, the latter consciously and only fairly accurately.
I often think of singing the note, so I have an idea of the pitch in my head, to aim for. Listening to the chord with the drones - if these are in tune - also helps with some notes. It is the notes that harmonise with the drones which are most exposed if out of tune, so recognising a just 3rd or whatever tells you you've got there. The singing trick doesn't work so well if you are still thinking equal-tempered, mind. So chords are better. Long notes are good practice for this - I wonder if this is one reason Tom Clough liked playing hymn tunes? 'Oh God our Help in Ages Past' (aka St Anne, or 'The Goldfish') is a good one for this, dead slow. I sometimes use this to see if the drones are 'really' in tune. When I started playing NSP after playing the flute for years, my embouchure would bend to try to bring notes in - ineffective of itself, but I found I was doing something useful as well, as the notes came more into tune (I pinched a non-existent thumbhole to get the top octave on the whistle, as well). That first set I had needed a bit of variable squeezing to bring some notes close to where they should be. Intonation is a mystery on most instruments, and the hardest part to get right. A related issue is tone colour - finger vibrato alters the harmonics of a note substantially, changing the colour a lot; pressure vibrato much less so. Taking a lower finger off the chanter may vary the pitch up or down, so you can use finger vibrato to improve the intonation as well as the colour. Or worsen the intonation, if you use the wrong finger. Knowing which lower finger moves which notes in which direction is something one ought to learn. I tend to use the same finger whatever, if it works. John -- To get on or off this list see list information at http://www.cs.dartmouth.edu/~wbc/lute-admin/index.html