Every layer, every ingredient is an opportunity to add more flavor. Store bought shells taste like cardboard, ground turkey is healthier but doesn't taste as good as beef, iceberg lettuce tastes like tap water, pre shredded cheese has lost at least half it's flavor. GTFO with those. I know so many people who go on and on about their hot sauce and it's probably because it's the only thing with any flavor in the entire taco. I used to simply "like" tacos until my wife (Mexican) opened up my eyes and taste buds to the true glory of a home made taco.
Put some oil in a cast iron skillet and heat it to around "deadly". Carefully put your tortillas in with tongs and turn them once they puff up and clearly cooked. Remove to a paper towel to drain and cool a bit. This is a pain at first but worth it. We rotate between ground beef, shrimp, fish, and steak. Chopped up leafy green lettuce mixed with cilantro. Diced roma tomatoes. Finely chopped yellow onions. Fresh grated cheese. All prepped in advance. I usually get 3, one straight up, one with sour cream, and one with some Chillupa(sp) sauce.
The ground beef or steak get taco seasonings. The fish (Tilapia) and shrimp (popcorn) get a lot of cayenne and are cooked in clarified butter (again , a bit of a pain but worth it). Sometimes I'll do the fish with only cole slaw as a topping. Taco night is a big deal and usually the first meal when her family visits. The leftovers go into all kinds of tostadas and taco salads and such so we go overboard.