Different ways to keep a neutral larynx while singing?

Over the past few weeks I've been correcting problems with my voice
(eg. i'm breathing using my diaphragm now, getting used to raising my
soft palate) but the thing I've had problems with is keeping a neutral
larynx. I've been singing "Mum" over the major scale but I'm not sure
if it's even doing anything. Are there any other ways to correct this?

Thanks