Gender Scan

So I go in Wednesday at 16 weeks for my Gender scan because my Dr said we could tell by then! I have a few questions as to what should I do before the ultrasound to makes sure we get to see the little ones privates!! Lol I know a lot of ppl say orange juice but does it actually work?? I know my little one moves around already because I have a doppler & it's moving non stop when I try to hear the heartbeat. So what do u guys think??