carefully, gently
gradually, slowly
quickly
Cristina blushed and quickly lowered her eyes.

down

into
She lowered herself into the driver's seat.

onto
He carefully lowered the sleeping child onto the bed.

to
She lowered herself down to the floor.

Lower is used with these nouns as the subject:
eye

Lower is used with these nouns as the object:
age, anchor, arm, barrier, bill, binoculars, blind, boat, bow, casket, ceiling, cholesterol, coffin, consumption, cost, dosage, duty, emission, expectation, expense, eye, fare, fee, flag, flap, forecast, gaze, gun, head, heat, hood, immunity, intake, level, lid, limit, morale, payment, premium, prestige, price, profile, rate, rating, resistance, risk, sail, shade, shield, sight, speed limit, stake, standard, status, tariff, tax, temperature, threshold, value, voice, voltage, volume, wage, weapon

Lower is used with these nouns:
animal, atmosphere, back, berth, body, bracket, chamber, chest, class, classification, corner, court, deck, edge, end, eyelid, flank, floor, gum, half, intestine, jaw, layer, leg, level, likelihood, limb, limit, lip, mammal, management, part, portion, slope, storey, surface, thigh, third, torso, valley