There could be lots of reasons for this. Is it too wet? Or too dry. For watering purposes, wait until compost is dry then water well and let drain. It is better to give too little water than too much. Take off any yellowing leaves. Mist the whole plant with sprayer . Give plenty of light. Also haveyou been feeding it regularly. Use a general multi fertilizer following directions. Maybe if Tbird reads this he/she might give you futher advice. Cheers Skylight