In general the Spanish have a very modern outlook on clothing. They are keen on designer clothes but quality is more important than a designer name. Spanish made clothes tend to be high quality and reasonably priced.
Teenage girls tend to wear trousers more than skirts. Denim is definitely 'in'. Teenage boys are keen on designer wear and appearance is important to them. Mature Spaniards dress conservatively and with style. Older men in particular tend to wear high quality clothing.
It is unclear what the Spanish think of scantily clad holiday-makers but it is not acceptable in small villages, away from the coast. One should be particularly careful of dress code if entering churches. Swim-wear and short skirts are frowned upon.