two girls in early 20s travelling eastern europe in summer!?

We are going to Macedonia, Serbia, Exit Festival, Montenegro and Croatia. Any tips? We arent planning it too much just going with the flow seeing who we meet and where we stay. We have accommadation sorted in Macedonia and Serbia. Any advice on things we may not have thought of?

No, have fun. Exit is great this years, as always. Don't anything that you wouldn't do in your own country.

Have you the visa to visit these places. Furthermore, what about finance. Find out the currency they are using against yours and the exchange rate.

That's the way to do it: go with the flow, as it's the dominant lifestyle of the area. Enjoy yourself! Don't worry too much about anything really, as people are quite relaxed and generally hospitable, especially to two young girls!

Be careful..
Serbia and Croatia aren't the safest places right now.... well, moreso Serbia and Bosnia..

How long are you going to be here? Definately see Lake Ohrid in Macedonia. It's beautiful there. Also, leave some time to go "na gosti" with the locals. People here in Macedonia are very friendly.