It looks like you're doing a pretty good job already. If there's anything I would do,it would be to;move it to a larger,deeper pot. The one you have looks like a Crinum which could grow quite large. They will grow in a wide range of soil Ph,but they will use fertilizer better,and be greener in more acidic soil. The addition of iron sulphate in more dilute concentrations than you would use on a lawn,will help green it up,even at a less acidic Ph. When you move it, try to take great care not to disturb its roots. Disturbing them will keep it from blooming. Most of them bloom in the late spring and summer. They like more water and fertilizer then. As a matter of fact,in the south,heavy rainfall over several days will trigger a bloom cycle.
Del

I've got no idea how to grow them indoors. Mine are all in the yard. Full sun to part shade, they often won't bloom for years after being transplanted. Usually don't need fertilizer but in a pot you might want to give it a dose of one with a high middle number. They bloom in spring and fall here.
Tally HO!