STRENGTH TO STRENGTH
to gradually become more successful
DAY BY DAY
gradually over many days
EYE TO EYE
to agree with someone, or to have the same opinion as them.
ON AND ON
continuing for a long time
NECK AND NECK
Equal in a competition
HAND IN HAND
with hands joined, especially as a mark of affection.
STEP BY STEP
one at a time in a particular order
FACE TO FACE
talk directly to them, not by phone, email, online, etc.