The sites in Ronda are fantastic. The old bridges, the old castles, old building and the views.   Ronda is not large and the main sites are close to each other. 

You must take in the Plaza de Toros. There is much history attached to it.  It has a great museum, included in the price of the self-guided tour. 

The old town is full of day trip tourists during the day (and all the more fun for it) but very quiet at night when you will want to try out  the restaurants and bars on the north side of the gorge. The Spanish have a passion for shoes and there is a great shop opposite the Plaza de Toros (Bullring).   If you are planning on buying footwear the prices in Ronda are about 40% less that in Seville.  

For those with a car and an interest in Roman sites don't miss a visit to  Ronda La Vieja a few kilometers north west of Ronda (take the A374 and turn right onto the MA449). There is free entry to this large but only slightly excavated site but a magnificent Roman theatre set among wonderful countryside.

The Banos Arabes (Arab Baths) is one of the best preserved examples of Arab baths in Andalucia, and located just below the walls of the old city center. The museum is operated by the city of Ronda, and entry is 3 Euros. Aside from the very well preserved structures, there is  a good interpretive video in Spanish and English that explains the history and purpose of the baths.  These are well worth a visit and admission can be free if you like pick the right day. 

The Vino/Sherry Museum is a possible quick stop, but very little is written in English to read and you get to taste only 3 small glasses of wine with a plate of smoked meats, cheese and breadsticks.

Please give Ronda more than just a day. There is plenty to do for at least 3 days.  The journey from Malaga by hired car or bus is amazing, albeit with lots of bends!  Travelling on the very slow train from Algericas was fantastic. Despite arriving in Ronda very late, boy was it worth it, passing breathtaking scenery and wonderful little villages.  Just chill out and enjoy - with a bottle of Rioja would be even better!