Close where we stayed, the YH Giralda, were 2 good little restaurants, reasonably priced and open. 1) was the Moderna at the base of Gago and Abades. We enjoyed good dry white wine and calamari, which was very light. It comes with a salad and is enough for 2 to share. 2) We happened to wander into a new establishment, Gago6. At 1st we tried the white wine. It was not to our liking, being a little too young and green. The Rioja was fine, and went well with a few tapas. We tried 3: a) The eggplant mixture, baked with tomatillos and a cheese topping. b) The curry chicken breast with Israely couscous, tomatillos, currents and pine nuts. c) Their special house shrimp salad. A and C were our favorites. Prices were reasonable.
Tried a Rick Steves recommendation, Azoteas. Because we were close, we tried Azoteas' new location on Gago. Yes, we spent more, but it was worth it. Great food and wine choices. The wait staff are knowledgable, young and fun. As with most of Seville, if you order by the glass, it seems the same cost as a bottle. Since we ordered white for some dishes and red for others, by the glass, or "copa", worked well. Tapas plates may only be ordered at the bar. However, mid-size plates worked well. For instance, a cup of gazpacho prior 2 mid-sized plates was perfect for 2 people to share. We had cheese filled rice paper triangles (with white wine) and pork cheeks with potatoes cooked in a red wine sauce (with red wine). Both were recommended, and not the most expensive, but definitely worth it. Ask the waiter what works for you. They were very helpful. One point to remember, they put down bread and olives. This normal in most tapas places. They charged $3 EU. So ask if they're free. We did not. If not and you don't want them, tell them no.