The more your baby nurses at your breast the more the supply will be .so try and direct breast feed more.also pumping at frequent intervals may help in increasing supply. Apart from that lots of fluids ,daal, oats keeping yourself well hydrated,and decreasing stress are common sense things to increase supply. You can try lactare granules, satavari etc to increase supply too. How to latch is difficult to explain in text.there are a lot of helpful YouTube videos regarding helpful positions and tips for a successful painless latch.you may explore them.la leche league is a helpful resource