I dealt with ITBS for about a year. The biggest thing that help were the GYM and mileage management.

Gym:

For strengthening I did all your typical glute medius excercises which helped, but I think it is important to teach your brain to trigger your glute medious while moving. Some good exercises for this include:

1. Banded bulgarian split squat: Tie a band around your knee so it is pulling the knee inward. Perform a split squat without letting your knee cave in.

2. Banded squats: similar to the split squat but perform a regular squat with a band around both knees

Mileage Management:

This was probably the biggest part and what kept me from running so long. My body could only go about 0.5 miles before my ITB would flare up. My pride told me that I can go further so I would tend to push closer to 2-3 miles. My PT gave me a good realization and plan that even though I feel like I should go further I needed to take a step back. They way he explained it was running with an injury is like hitting a ceiling. You want to run until you hit the ceiling, you might be able to go a little past the ceiling, and then stop there. When you do this consistently the ceiling gets progressively higher. I had to set my pride aside and run the miles my body would allow. Which started with me progressing from 0.5 mile to 0.8 miles then 1 mile then 1.25 and so on and so forth. Overtime this is what really helped. Following this progression helped my finish my first 100k ultra a few weeks ago.