If you go by boat from Spain, I recommend getting out of the port as quickly as you can, and finding a tour guide once outside (or having them find you!). The tour guides are actually pretty friendly, seriously cheap, and they keep everyone away from you… anyone who might try to sell you things or bother you. They take you to the nice places, and, of course, recommend shops where they get a cut from what you buy, but hey, better than having people bugging you during your entire stay!