In my experience, the hybrids containing besseae and the caudatum types in the background seem to be finicky bloomers compared to most other phrags. They often take many years to bloom, even after they are mature sized with multiple growths.
You can definitely try increasing the amount of light, but if possible, make that adjustment slowly. Since this is a phrag we're talking about, I wouldn't bother increasing your fertilizing rate. Unless you're seeing clear signs of a nutrient deficiency, then the plant's probably getting enough of everything it needs.
Wallisii does like to grow a bit drier than the average phrag, but if you've been successful growing your hybrid plant in wetter conditions or sitting in water, then there's no reason to change that part of your culture. Growing drier isn't likely to increase the chance of the plant blooming. My only advice would be to keep a watchful eye out for rot. With these kinds of crosses, individual plants have variations in their preference and tolerance for wet conditions. If your plant has been fine growing wet, though, then it will likely continue to do well growing that way.