I had a preemie and I need pumping tips

This 21st of May I had a baby via c section, I was 34 weeks pregnant. Had placenta accreta and I lost a lot of blood, was out of it for the first three days. On the 4th day when I was ok I request a pump but the lactation consultant never went to help me. Called the WIC and they said till Tuesday they will help me out. I've been pumping every 2hrs for 15 minutes each breast but sometimes I only get milk from one breast, and I also produce very little milk. I produced even a tinier amount of colostrum(just glad the nurses give my baby what very little I make) 
I just wanted to ask, if anyone has any tips on how to produce more milk? How to effectively pump? Techniques? Any tips, suggestions are very much appreciated!! 
TIA