How to increase milk supply???

Any suggestions on how to increase milk supply? This is day 4 since my milk came in and my baby is 1 wk and a day old. I have been nursing every 3 hrs for 20 mins total on both boobs, pumping usually after feeding and I only get about 1/4 to half an oz. The most I got was 1oz. I have been drinking a lot of water, fruit juice, fruit smoothie, nutritional shakes mixed with lactation powder but it seems like there is no improvement. I'm desperate to breastfeed and give my baby the best I can. Please help. Thanks!!!!