persistent
incessable
sticktoitive
urgently
patient
high-pressure
hard-hitting
ongoing
resting
steadily
steady
steady-handed
unbrokenly
if at first you don't succeed
inveteracy
the whole while
lingeringly
nonpersistently
persistency
pressing
fierce
persistability
invariable
twenty-four seven
without cease
steadiness
impersistent
expediency
obstinate
longevity
unflinching
game
unsatiably
sedulousness
permanently
lasting
perduringly
tenuto
insatiably
unfailingly
continuum
unremitting
unstraying
scrub
continuedly
if at first you don't succeed, try try again