Browning leaves can happen from both over- and under-watering your ivy. Be sure to let the soil dry out 25-50% of the way down before watering your plant. In the winter, you can err on the dry side. Always be sure to test the soil before you water.
When you water, make sure you provide enough water so that liquid soaks into the soil and flows from the drainage hole at the bottom of the pot and into the saucer. It’s extremely important to discard any excess water in the saucer, to avoid root rot.
Your ivy thrives in a humid environment! Browning leaves can be a sign that the humidity is too low. Boost the humidity in your home by adding a humidifier nearby, creating a pebble tray, or misting the plant often.
Brown crispy leaves can be a sign your ivy is getting too much light. Ivy plants prefer indirect bright light from an east-facing window, or a few feet back from a south- or west-facing window. If placed in too much direct sunlight, your ivy leaves will burn.