i start with scales, and supposedly hanon but i've given up on them. then i'll go through my pieces either in order of what i'll be playing in the exam, or if something's in great need of help then it goes first...oh no it doesn't i always do my bach prelude (from the english suite in g minor) first cos i warms my hands up well, then i'll do the piece that needs saving.
if i'm learning a new piece, i always think i should practice it first, but due to liking being in my comfort zone i'll usually start with my already known pieces, though i shouldn't because then the new piece'll get neglected at the end