To save you money and possible arguments with bar staff, it's best to be aware before you go. Paying a cover charge, and buying individual drinks in the discoteca. Some discotecas will issue you a debit card when you enter.
This is then presented to the bar staff instead of paying with cash.
Closing times vary by city, however most regular bars close by 2 – 3 AM. Dress codes apply to a minority of discotecas in the major cities.
99% of the time you won't need to worry about dressing up for a night of partying in Ecuador.
An hour after entering, we decided to go somewhere else and were surprised to learn each guy had to pay a cover, and each woman had to pay a cover (and men are expected to pay for their dates in Ecuador, always).
Every Ecuadorian city features a Zona Rosa, or main nightlife district, where you'll find the highest density of bars, discotecas (clubs), and restaurants. In Guayaquil, there are a few places, with Las Penas being the safest and most easily accessible.
In Cuenca, you'll find the Zona Rosa along Calle Larga, within easy walking distance of the historic center.
The best approach is to be friendly and straightforward.
The guys should ask a girl to dance, or start a casual conversation. To enjoy yourself, take a few salsa lessons (/hour for private lessons).
Also, the surf town's casual vibe and relaxed policies on marijuana attract lots of other South Americans from Argentina, Chile, and Colombia, as well as foreigners from around the world.