Firstly concentrate on ur sleep & diet.You must take 8 to 9 hrs. night sleep,not more or less.Your diet should include all healthy food such as chapati, subji ,dal,cereals, rice,salad, milk,all fruits, dry fruits.
Eat 2 spoons of fresh home-made butter daily.take home-made ghee on rice ,chapati.
1 tsf Chavanprash daily in d morning will increase ur appetite.
If u have any addiction like tobacco,it is not at all good for health.
Do muscle exercises
regularly,also have protein supplements
keep ur mind always fresh & healthy.You will achieve a good health.