Belgrade (Beograd in Serbian) is the capital of Serbia, home to around 2 million people. The main motorway (Autoput in Serbian) runs pretty much close to the centre of the city from the North West to the South East. Most cars also use this as a normal road so hitching out of Belgrade is quite difficult.
Heading South East[]
Towards Nis, Sofia (Bulgaria), Skopje (Macedonia).
First, from Trg Studentski (Students Square) or Trg Slavia (Slavia Square) get bus number 31 all the way eastbound (i.e., not to Trg Studentski) to the end of the route (you should see a lot of market people selling fruit on the right side of the bus). The bus closely follows the route of the motorway. From here, you leave the bus and it's a 10-minute walk straight down hill to the actual motorway.
You have 2 choices, you can either go west along the motorway to try to find an entrance ramp, or alternately 2 km east is a petrol station, however, you have to either walk along the motorway, or through the grass on the verge, however, this gets very thick at times - it's pretty easy though, just hard work :)
If you're heading for Nis (or beyond) try using a sign (saying Nis) - remember to leave the car *on the motorway* - not in Nis, unless you're a big fan of walking.
Towards Banja Luka, Doboj, Tuzla (Bosnia)
Take the buss number 511 from the trainstation and watch the street. The bus ist leaving the street that leads to Šabac after about 20 minutes. That's the point where you get off and walk back to that street. Hitchhike in small steps, you wont find somebody driving directly to Bosnia. Hitchhike to Šabac first and than to Bosnia. In Šabac youwill find a good place for hitching at the petrol-station about 2,5 km behind the city.