Velenje is an important city in central Slovenia, which was used to be called "Titovo Velenje" after the name of the city's founder. It has a population of about 27,000 inhabitants, and it boasts a castle, a thriving center with an enormous statue of Tito and free wireless connection, a famous ski-jumping site, and a large Bosnian population.
Hitchiking out of Velenje is very easy, in all directions.
From the old city center, below the castle, walk up Celjska cesta, for a few hundred meters. Soon the city will end and you will find on your right a convenient place for the cars to stop - If you go to Celje then it's best to get a ride that passes the motorway entrance in Zalec, and continues directly to Celje (it's about 18km) To Ljubljana or any other city on the motorway, you can try and hitchhike directly from Velenje, or better yet get off in the Zalec motorway exit and hitchhike with a sign from there.
Direction of Slovenj Gradec, Dravograd, and Austria
From the old city center, walk on Šaleška cesta which is the continuation of the main road after the bus station (see map). After 400m you will pass on your left a shopping center, then on your right a petrol station, and just before the tunnel ahead there will be a bus station on your right. Hitchhike from there with or without a sign.
From the main street, West of the Train station (Dunajska Cesta) take buses 6, 8 or 10 in direction of North. Get off in the station "Smelt", 15 minutes later, when you see the "World Trade Center" building. Ahead of you, you will see the Autostrada. On the first turn to the right, go into the motorway entry and stand on the side with your sign. You can hitchhike with a sign VE for Velenje - you might get a direct ride, but else you can also get a ride to the motorway exit Zalec (the driver can easily exit an re-enter) and continue hitchhiking there towards Velenje. In the exit there is a great spot, walk 100m in direction of Velenje and you will reach a bus station with ample of space for cars to stop.