Good local restaurants are not hard to find, every area has many restaurants that severe good quality Sichuan food. The art only is to know what to order and find a good balance in your choices. If you are not familiar with reading characters or menus, my advice is to look at what others eat, order and write down/remember the name. Or read thru the guide thats on ChengduLiving.
More cheap looking restaurants, ‘whole in a wall’ restaurants, offer the most basic and famous homestyle sichuan dishes. Fancier places offer a more fancier version obviously but also fancier Sichuan dishes. For something different I really like this place DaDongBei 大东北，in Wuhouci area.