When driving in Belgrade, do look for police waiting for speeding cars especially on the bridge to Kotez. Also do look for them in Splavovi at night on the weekends. Speeding and driving under the influence is not tolerated at all.
When dining in restaurants do order a srpska salad or kupa salad or a soup as it seems that every meal is ordered with one of these and waiters will assume you know this.
Don't order wine before 5-6pm at sidewalk cafes because the waiters and cafe goers will assume you are a tourist and do not know how to order coffee at a cafe. (Based on my own experience).
Do eat biscuits, proja or burek in the morning with coffee at a nearby cafe. People do not eat big breakfasts or proteins in the morning. They do drink a lot of yummy yogurt drinks with fresh bread and mladi sir. When you go to a cafe for breakfast you will most likely be eating a sandwich and salad, oh and did I mention coffee, coffee, and more coffee.
Ladies don’t drink beer from the bottle, actually they do not drink beer at all. I have witnessed them drinking mainly wine and some popular cocktails like mojitos and fruity martinis. And while we’re on the subject, most kafes, lounges and clubs do not supply the basic ingredients, (no cranberry juice to be found) to make many simple cocktails, like Vodka and Cranberry. Cranberry juice is only found in pharmacies to boost immunity and physical health. If you want to order a bottle of vodka at a club, all mixers are not complimentary and you must pay for tonic water, orange juice and soda water.