Now: creative parking is everyday routine, just be sensible. Probably you're German or Austrian so this whole stuff doesn't make sense to you, but: avoid bus stops and spots for disabled and you'll be fine. Always pay the meter. If you're staying more than a couple of days you might as well register on EasyPark and download the app. It will make things easier, not having to worry for the meter running out: you simply pay by credit card. If you're technologically impaired, we won't laugh in your face: drop by our office and we'll set up the app for you. Plus you get a free coffee.
If you're planning to visit Croatia or Slovenia, watch out for the highway tolls. Slovenia works on a Vignette (toll sticker) system. These are the prices. Basically 15€ for 1 week. Buy it as soon as you can, or else you'll get the fine + you'll be obliged to buy a yearly one.
In Croatia there's no need for toll stickers, you simply find random tollbooths in which you can pay in Euros and get the change in local currency (Kunas). Remember to have your ID with you (and make sure you haven't massacred it in the washing machine) or else you'll be rejected at the border. Last: line up your neurons before deciding to cross the border in summer on Friday evenings and Sunday nights. At least bring a bottle of water with you.