I got chili peppers from Thailand growing. What can I do for them to help flowers?

If you told me they weren't GMOs I wouldn't believe you because they grew so, so fast and they're super resilient. I know chili plants are more resilient than other species, but I've never seen something like this.

However only one plant is giving me flowers, the others not yet. Can I do something to help flowers grow into fruit? Prune leaves, for example? I seriously have no idea about gardening beyond giving plants water and sunlight.