Be considerate and careful where you park your car. The shore is accessible to everyone but keep in mind that that access has been created by a homeowner, possibly the homeowner who also wheelbarrowed tons of rocks and dirt to make some parking spaces in front of his house. You don't want to be taking up that space; you may return to your car and find the tires somewhat empty of air or a window broken or a nasty note on your windshield. It's a good idea to knock on the house's door wehre an empty parking space is and check out the situation. A few kuna may help you ease the relations. if you're stopping in a smaller village especially, try to keep the natives restful.
Croatia is knows for it's rocky beaches and this may pose a problem as some of them are very sharp and can hurt you...I myself have been cut multiple times and recommend wearing sandals while entering the water.
There is such a great nightlife in Makarska that some party just a little too much which can result in an aftermath like my 2 friends:-)