You try to give exclusive breastfeeds till 6 months of age.
Hope you are taking your iron and calcium supplements
. Do not take both at the same time as absorption will be interfered.
You must eat healthy diet- with adequate fluids, milk, fresh fruits, lot of pulses, dry fruits- dates etc. If you are a non-vegetarian, you may have eggs, non-veg food too.
Take adequate rest- do not resume your normal works early.
You may ask your doctor for medications like Domperidone
that can increase milk output to some extent.
Be confident that you can feed her with breast milk alone for 6 months.
More confident you are, more love and affection towards your baby, more will be the milk output.
Once you start supplementing with formula milk, baby will be easily satisfied, less will be the sucking and your breast milk output will reduce.
At a time, feed her from both your breasts so that she drinks to her satisfaction and sleeps off. If she sleeps off in between without feeding fully, arouse her by gentle strokes on her feet/ ears.
Have her weight checked, if she is gaining weight adequately, there is no need to supplement her.
If her weight gain is not sufficient and your breastmilk output is still low, then you may opt for formula. The mode of preparation will be given on the pack (one scoop for 30ml of warm water). And the amount will be decided by your baby. If at all you decide to supplement her- do not use bottles. Its preferable to give it with spoon.
Breast milk is the best for your baby in numerous ways.
Hope my answer helps you.