piece by piece
Incrementally; slowly; one piece at a time. You don't have to overhaul your diet overnight—just start making healthier choices piece by piece. It took years, but piece by piece we turned this ramshackle old house into a real home.
piece by piece
In stages, gradually, as in He took the clock apart piece by piece, or Let's go over your exam paper, piece by piece. Also see bit by bit.
ˌpiece by ˈpiece
one part at a time: He took his motorcycle apart piece by piece, cleaned it, and put it back together. piece by piece
In stages: took the clock apart piece by piece.