It sometimes seems that there are new tapas bars opening up in Seville almost every other day, which keeps me happily busy as I usually go out for tapas at least a couple of times a week. In Seville that is the most usual form of eating out - the tapeo - which involves going to two or three different bars having a couple of tapas and a drink at each one.
Eating times vary slightly, but breakfast is usually from 8am-noon, lunch is served between 1-4pm and dinner from 8-11pm. Often the bar will close from 5-8pm but in the centre you will find many places stay open serving drinks and cold snacks. Not all places open for breakfast either and most take one day off during the week.
You can also find lunchtime menus (in Spanish a "menu" is a fixed price meal and "carta" is the word for menu) for about €10 that include three courses (starter, main course and dessert) and a beverage (wine, beer, mineral water or soft drink). These are often good value for money and are served up quickly, making it a good choice for people on their lunch break or tourists who don't want to linger over a meal.
Having said that, tapas are the original fast food, so unless you are at one of the newer gastrobars you will probably get your food within a few minutes after ordering. With this in mind, it is a good idea not to order all your choices at once. I usually order one round of tapas to start and then order the next when the first one arrives. If there are more than two of us we might share a ración, which is basically a much larger tapa.
The main disctinction I make here between tapas bars and restaurants is that restaurant menus will offer starters and main courses much as you are used to seeing at home. In tapas bars the food usually comes in three sizes: raciones (like a main course serving), media-raciones (half-sized) and tapas (small snack-sized dishes). And when I refer to a tapas bar/restaurant this means there is a separate restaurant area with a different menu from the one at the bar.